Columbia  ^mbers:itp\^^  y 
ttttl)t€itpct3attoiork 


l&tfnmtt  SItbrarg 


S)^r^<-^      ^/'Sv^OcV^.W^.r. 


THE 

FRED.  J.  BROCKWAY, 

LIBRARY, 

College  of  Physicians  i  Surgeons, 
New  York  City. 


Illustrations  of  Dissections 


^i^vus  ot  O)tri0inaX  (<^oXoved  glates 


THE    SIZE    OF    LIFE 


REPRESENTING    THE 


DISSECTION    OF    THE    HUMAN    BODY 


BY 

GEOEGE  VINER  ELLIS 

PROFESSOR    OF    ANATOMY    IN    UNIVERSITY    COLLEGE,    LONDON 
AND 


G.  H.  FORD,  Esq. 


THE  DRAWINGS   AEE  FROM  NATURE   BY   MR.    FORD,    FROM   DISSECTIONS 
BY   PROFESSOR   ELLIS. 

{Reduced  un  a  uniforin  scale,  and  reproduced  in  facsimile,  e,cpret>Kli/  for 
Wood'fi  Library  of  Standard  Medical  Authors.) 


^ejcond  ^ditijcm 


TWO  VOLUMES  IN  ONE -VOLUME  I. 


NEW  YOEK 

WILLIAM    WOOD     &     COMPANY 
1891 


Digitized  by  tine  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/illustrationsofOOelli 


PREFACE. 


This  Yolume  contains  a  concise  description  of  a  series  of  Anatom- 
ical Plates  in  folio  in  a  separate  Altas  (in  this  edition  the  Plates  arc 
bourd  with  the  text. — Am.  Publishebs),  with  some  remarks  on  the 
practical  applications  of  Anatomical  facts  to  Surgery.  The  purpose 
for  which  the  Plates  are  designed,  and  the  circumstances  connected 
with  their  production  are  explained  below. 

Witli  the  view  of  carrying  out  the  pictorial  representation  of  dis- 
sections, the  part  of  the  Human  Body  to  be  illustrated  is  divided  into 
suitable  stages  or  regions ;  and  the  muscles,  bloodvessels,  and  nerves 
of  each  region  are  shown  in  layers  in  the  natural  Order  of  succession, 
so  that  their  mutual  connections  may  be  brought  before  the  eye  at 
one  and  the  same  time. 

The  Illustrations  comprise  views  of  the  Head  and  Neck,  the  upper 
Limb,  the  Perinseum,  the  Abdominal  parietcs,  the  Pelvis,  and  the 
lower  Limb.  All  the  Figures  are  drawn  of  life-size  from  actual  dis- 
sections ;  and  they  are  printed  in  colors  with  the  object  of  making 
them  as  true  pictures  as  possible  of  Nature,  and  more  serviceable  as 
copies  for  the  student  to  imitate.  Only  such  dissections  were  pre- 
pared for  the  Drawings  as  may  be  commonly  seen  in  the  practical 
Anatomy  Room  ;  and  the  minute  detail,  whose  counterpart  the  stu- 
dent with  average  manual  dexterity  could  not  produce  without  some 
difficulty  and  loss  of  time,  was  intentionally  omitted.  Delineations 
of  the  ligaments,  the  viscera  of  the  cavities  of  the  Body,  and  the 
organs  of  the  Senses,  are  not  included  in  the  Plates  now  published. 

The  labor  connected  with  this  Work  was  divided  between  its  two 
authors,  that  part  being  apportioned  to  each  which  he  was  best  fitted 
by  previous  knowledge  and  experience  to  execute.  To  Mr.  Ford 
were  assigned  the  original  Drawings,  and  the  chromo-lithography ; 
and  to  him  is  due  the  merit  of  portraying  with  so  much  effect  and 
exactness  the  natural  appearance  of  the  parts  dissected.     Upon  me 


IV  PKEFACE. 

rests  the  responsibility  of  the  selection  of  the  Illustrations,  the  fidelity 
of  the  dissections,  and  the  accuracy  of  the  whole. 

Dui'ing  the  progress  of  this  undertaking,  which  was  continued 
through  several  years,  other  engagements  necessitated  my  having 
recourse  occasionally  to  the  senior  Students  of  the  College  for  the 
.  help  of  their  hands.  To  those  Students,  and  to  Mr.  Samuel  Onley 
in  particular,  I  gladly  offer  my  thanks  for  their  assistance.  And  to 
the  late  Mr.  J.  S.  Cluif,  Demonstrator  of  Anatomy,  I  am  greatly 
indebted  for  the  valuable  aid  he  afforded  me  at  all  times. 

Before   closing   this  -retrospect  of  the   task  now  finished,  I  may 

advert  to  the  diflBculties  attendant  on  the  printing  in  colors  of  such 

complicated  Figures,  and  to  the  successful  way  in  which  they  were 

overcome  by  Mr.  "West. 

GEORGE   YINER   ELLIS. 

Unh'.  Coll.  Lond., 
May  \st.  1876. 


CONTENTS. 


THE    UPPER   LIMB. 

PAHE 

Plate  I. — The   superficial  muscles   of  the   thorax,  and   the  axilla 

WITH   ITS  contents 1 

Superficial  thoracic  muscles 1 

Boundaries  of  the  axilla .         .  3 

Arteries  of  the  axilla 5 

Veins  of  the  axilla 9 

Nerves  in  the  axilla 10 

Nerves  of  the  brachial  plexus 10 

Lateral  cutaneous  nerves  of  tlie  thorax       .         .         .         .  11 

Lymphatics  of  the  axilla 12 

Fat  in  the  axilla 13 

Plate  II.— The  axillary   vessels,    and   brachial   plexus   of  nerves, 

WITH  their  branches 14 

Superficial  prominences  of  bone  ......  14 

Deep  muscles  of  the  thorax 16 

Axillary  artery  and  branches        .         .         .         .         .         .  19 

vein  and  branches       .......  24 

Brachial  plexus,  and  its  branches 25 

Lymphatic  glands 26 

Pi^te  III.— Superficial   "s'eins   and   nerves   in   front  of  the  bend  of 

THE  ELBOW 27 

Fascia  of  the  limb,  and  the  biceps        .....  27 
Cutaneous  veins  and  blood-letting,  with  injuiy  of  the  bra- 
chial artery 28 

Brachial  artery,  with  ligature  of 34 

Cutaneous  nerves  at  the  elbow        ......  36 

Plate  IV.— Superficial  view   of   the   arm   on   the   inner  side,  with 

the  parts  undisturbed  .        .        .        .        .        .        .  37 

Surface-marking  of  the  arm 37 

Fascia  and  muscles 38 

Veins  of  the  arm 40 

Brachial  arterj-.  its  ligature,  and  branches    ....  41 

Nerves  of  the  arm 46 

Lymphatics  of  the  arm     ........  47 


^  CONTENTS. 

PAGE 

Plate  V. — The  shoulder,  and  the  muscles  at  the  back  of  the  scap- 
ula    48 

Scapula  and  shoulder  muscles 48 

Arteries  of  the  shoulder 52 

Nerve  of  the  shoulder 68 

?LATE  VI. — The  triceps  muscle  behind  the  humerus,  anu  some  shoul- 
der MUSCLES 54 

Triceps  extensor  muscle,  and  fracture  of  the  olecranon        .  54 

Arteries  of  the  arm  and  shoulder          .....  56 

Plate  VII. — The  musculo-spiral  nerve  in  the  arm,  and  the  profunda 

VESSELS 58 

Muscles  of  the  arm  and  shoulder     ....  58 

Vessels  at  the  back  of  the  arm 60 

Nerv'es  at  the  back  of  the  arm 61 

Plate  VIII. — Surface  view  of   the   forearm,  with   the,   parts  undis- 
turbed       63 

Superficial  muscles 63 

Hollow  before  the  elbow 66 

Radial  artery  and  branches  :  ligature  of         ....  67 

Nerves  superficial  in  the  forearm         .         .         .         .         .  70 

Plate  IX. — Deep  view  of  the  front  of  the  forearm  ....  71 

Muscles  of  the  deep  layer 71 

Ulnar  artery  and  branches:  ligature  of        ...        .  74 

Nerves  of  the  forearm 77 

Plate  X.— Superficial  and  deep  views  of  the  palm  of  the  hand    .  78 

Fig.  i.  Central  muscles  of  the  palm 79 

Superficial  palmar  arch  :  wounds  of 81 

Superficial  nerves  of  the  hand 84 

Fig.  ii.  Short  muscles  of  the  digits 86 

Radial  artery  and  deep  palmar  arch 88 

Deep  nerve  of  the  hand 90 

Plate  XI.— Superficla.l  view  of  the  back  of  the  forearm  and  hand  91 

Superficial  layer  of  muscles 91 

Radial  artery  at  the  back  of  the  hand         ....  96 

Plate  XII.— Deep  view  of  the  back  of  the  forearm      ....  98 

Muscles  of  the  deep  layer  .         .            .....  98 

Arteries  at  the  back  of  the  forearm        .....  100 

Neiwe  at  the  back  of  the  forearm        ,        .        .        .        .  101 


CONTENTS.  Vll 


THE    HEAD    AND    NECK. 

PA62 

Pirate  XIII.— Base  of  the  skull,  and  first  and  second  views  of  the 

ORBIT 104 

Yossge  of  the  base,  and  parts  of  the  dura  mater    .         .        .  104 

Cranial  nerves  in  the  skull 106 

Vessels  of  the  base  of  the  skuU 109 

Highest  muscles  of  the  orbit,  and  the  lachrymal  gland     .  Ill 

Vessels  of  the  orbit 112 

Superficial  nerves  of  the  orbit il4 

Plvte  XIV. —Sinuses  of  the  dura  mater,  and  two  deep  views  of  the 

ORBIT 115 

Sinuses  of  the  dura  mater 116 

Deep  muscles  of  the  orbit         .        .        ,        .        .        .        .117 

Nerves  deep  in  the  orbit 118 

jr'LATE  XV. — The  anatomy  of  the  side  of  the  neck  behind  the  sterno- 

MASTOID  MUSCLE 121 

Lateral  muscles  of  the  neck     .......  121 

Posterior  triangular  space — its  boundaries  and  contents    .  124 
Arteries  in  the  space,  and  ligature  of  the  third  part  of  the 

subclavian 127 

External  jugular  vein  and  blood-letting      ....  131 

Nerves  in  the  triangular  space 133 

Plate  XVI. — Sutiface  view  of  the  neck  in  front  of  the  sterno-mas- 

TOIDEUS  aruscLE 135 

Surface  objects  visible  without  displacement  of  any  part     .  135 

Sterno-mastoideus  and  the  fascia         .        .        .        .         ,  137 

Connections  of  the  saUvary  glands 138 

Superficial  arteries  of  the  neck 139 

veins  of  the  neck 140 

Cutaneous  nerves  of  the  neck 140 

F'late  XVII. — View  of  the  front  of  the  neck  after  displacement 

OF  the  sterno-mastoideus 141 

Anterior  triangular  space 141 

Anterior  muscles  of  the  neck 143 

Carotid  vessels,  and  ligature  of    .....         .  146 

Veins  of  the  front  of  the  neck 151 

NerA^es  of  the  fore  part  of  the  neck 151 


Vin  CONTENTS. 

PAGE 

Plate  XVIII  —The  subclavian  artery  and  the  surrounding  parts    .  153 

Muscles  of  the  subclavian  region 153 

Subclavian  arterj^  and  branches,  with  ligature  of  the  second 

part .  154 

Subclavian  and  deep  jugular  veins      ....'.  156 

Nerves  of  the  subclavian  region      .         .         .         ...         .  157 

Plate  XIX. — A  deep  view  of  the  back  of  the  neck    ....  159 

Deep  muscles  behind  the  spine 159 

Arteries  at  the  back  of  the  neck 160 

Nerves  at  the  back  of  the  neck 161 

Plate  XX. — Superficial  view  of  the  Pterygoid  region     .        .        .  163 

Muscles  of  mastication 163 

Internal  maxillary  artery  and  branches      ....  165 

Internal  maxillary  and  facial  veins          .....  166 

Branches  of  inferior  maxillary  nei"ve 167 

Plate  XXI. — Deep  view  of   the  dissection   of  the   pterygmdid  region  168 

Cranial  branches  of  internal  maxillary  artery       .        .        .  168 

Inferior  maxillary  nerve  and  branches        ....  169 

Plate  XXII. — The  anatomy  of  the  submaxillary  region   ,        .        .  173 

Tongue  and  hyoid  muscles       .......  172 

Salivary  glands  under  the  jaw 174 

Lingual  artery  and  vein 174 

Nerves  of  tongue,  and  the  submaxillary  ganglion      ,         .  175 

Plate  XXIII. — Upper  maxillary  nerve,  and  deep  part  of   the  inter- 
nal MAXILLARY  ARTERY 177 

Some  facial  muscles 177 

Terminal  offsets  of  the  maxillary  artery        ,        .        .        .178 

Upper  maxillary  and  facial  nerves 179 

Plate  XXIV. — Internal  carotid  and  ascending  pharyngeal  arteries, 

and  cranial  nerves  in  the  neck         .        .        .        .180 

Deep  muscles  in  front  of  the  spine 181 

Carotid  and  ascending  pharyngeal  arteries    ....  182 

Cranial,  spinal,  and  sympathetic  nerves  in  the  neck          .  184 

Plate  XXV. — External  view  of  the  pharynx  with  its  muscles          .  190 

The  pharynx  and  its  muscles 190 

Some  nerves  and  vessels  of  the  larynx 192 


CONTENTS.  13 

PAGE 

PiATE  XXVI. — Interior  of  the  pharynx,  and  the  muscles  of  the  soft 

PALATE 193 

Cavity  of  the  pharynx,  and  its  openings     ....        194 

The  soft  palate  and  the  tonsil 197 

Muscles  of  the  soft  palate,  and  use  of  tlie  part   .        .        .        198 

Plate  XXVII. — Larynx  and  vocal  apparatus,  with  the  muscles,  ves- 
sels,  AND  NERVES 201 

I'igs.  ii.  and  iii.  Cartilages  of  larynx,  and  hyoid  bone  ....  201 

Articulations  of  laryngeal  cartilages 204 

Interior  of  larynx,  and  vocal  apparatus      ....  206 

Fig.  i.  Muscles  of  the  larynx  governing  the  size  of  the  glottis  and 

the  pitch  of  the  voice 208 

Nerves  of  the  larynx,  and  use 211 

Vessels  of  the  larynx 213 

Thyroid  body  and  the  trachea      .         .         .         .         .         .  214 

t'LATi;  XXVIII. — Nose  cavity  with  the  boundaries  and  openings  into 

IT 215 

Cavity  of  the  nose  and  its  bounds 216 

S»ongy  bones  and  the  meatuses 218 

Mucous  membrane  and  bloodvessels 219 

Olfactory  region  and  nerves  of  the  nose  ....  220 


^-'^^v^^  •»,  -■ 


PLATt 


ILLUSTRATIONS  OF  DISSECTIONS. 


DESCRIPTION  OF  THE  PLATES. 


DESCRIPTION  OF  PLATE  I. 


The  superficial  muscles  of  the  thorax,  and  the  axilla  with  its  contents, 
are  delineated  in  this  Plate.  The  natural  size  of  the  dissected  part  has 
been  slightly  reduced  in  the  Drawing  for  the  purpose  of  showing  the 
whole  of  the  ujDper  limb. 

In  the  preparation  of  the  dissection  the  limb  was  drawn  away  from 
the  trunk  to  render  tense  the  muscles.  Next,  the  integuments  were 
divided,  and  the  skin  and  fat  were  raised  together  in  one  large  flap  from 
the  front  of  the  thorax  and  the  axilla  by  carrying  the  scalpel  upwards 
and  outwards  from  the  chest  to  the  arm,  as  the  fibres  of  the  muscle  run, 
and  along  one  muscular  fasciculus  at  a  time.  After-wards  the  fat  was 
cleared  out  of  the  axilla ;  and  the  muscles  bounding  the  space  behind 
were  laid  bare  in  the  same  way  as  those  limiting  it  in  front. 

MUSCLES  OF  THE  THORAX  AND  ARM. 

Two  sets  of  muscles  are  displayed  in  the  dissection  ;  one  bounding  the 
arm-pit  before  and  behind  ;  and  the  other  lying  in  front,  and  at  the  back 
of  the  humerus. 

The  former  group  are  directed  from  the  trunk  to  the  limb,  and  move 
the  limb  forwards  and  backwards  over  the  chest.  Where  they  are  fixed 
to  the  thorax  they  are  separated  widely  by  the  ribs,  but  at  the  arm-bone 
they  approach  one  another.  In  the  interval  between  them,  near  the 
humerus,  the  large  vessels  and  nerves  of  the  limb  are  lodged. 

The  muscles  of  the  arm  connect  the  limb  with  the  scapula,  and  assist 


^  ILLU8TEATI0NS    OF    DISSECTIONS. 

in  the  movements  of  the  shoulder  joint  :  they  will  be  more  fully  seen  in 
other  Plates. 


A.  Pectoralis  major. 

B.  Pectoralis  minor. 

C.  Latissimus  dorsi. 

D.  Teres  major, 

F.  Serratus  magnus. 
H,  Subscapularis. 


K.  Coraco-brachialis. 

L.  Biceps. 

M.  Fascia  of  the  arm. 

N.  Triceps  muscle. 

P.  External  head  of  the  triceps. 


The  pectoralis  major,  A,  reaches  from  the  chest  to  the  arm  over  the 
front  of  the  axilla.  By  its  inner  end  (origin)  it  is  attached  to  the  sternum 
and  the  cartilages  of  the  true  ribs,  except  the  last,  as  well  as  to  a  jDart  of 
the  clavicle ;  and  it  joins  the  tendon  of  the  external  oblique  muscle  of 
the  abdomen  below.  By  its  outer  end  (insertion)  it  is  fixed  into  the  bi- 
cipital groove  of  the  humerus.     Plate  ii.  P. 

The  muscle  forms  the  main  part  of  the  anterior  boundary  of  the 
axilla  ;  and  towards  its  lower  end  near  the  arm-pit  the  mamma  or  breast 
rests  on  it. 

Should  the  breast  be  diseased  so  as  to  render  necessary  its  removal, 
the  limb  should  be  placed  during  the  operation  in  the  position  shown  in 
the  Illustration,  and  the  scalpel  should  be  carried  in  the  direction  of  the 
fibres  in  detaching  the  mass  to  be  extirpated. 

The  jjectoralis  minor,  B,  is  extended,  like  the  preceding,  from  the 
chest  to  the  limb  in  front  of  the  axilla.  Only  a  very  small  part  is  now 
visible  :  for  a  view  of  the  muscle  see  Plate  ii.  B. 

The  latissimus  dorsi,  C,  resembles  in  its  position  behind  the  axilla 
the  large  pectoral  muscle  in  front.  Arising  below  from  the  spinal  col- 
umn, the  pelvis,  and  the  lower  ribs,  it  is  inserted  into  the  bicipital  groove 
of  the  humerus.  The  upper  edge  of  the  muscle  has  been  everted  in  the 
Drawing  to  bring  into  sight  the  vessels  and  the  nerve  lying  inside  it. 

Oftentimes  a  fleshy  slip  is  continued  from  the  latissimus  over  the 
axillary  vessels  to  join  the  pectoralis  major,  the  fascia  of  the  arm,  or  the 
coraco-brachialis  muscle. 

The  teres  major,  D,  lies  behind  the  latissimus,  by  which  it  is  partly 
concealed.  Attached  below  to  the  scapula,  it  is  inserted  into  the  humerus 
beneath  the  broad  muscle  of  the  back,  C. 

The  three  muscles,  pectoralis  major,  latissimus,  and  teres,  converging 
from  the  trunk  and  scapula  to  the  upper  part  of  the  arm-bone,  will  ap- 
proximate the  raised  movable  limb  to  the  trunk  when  they  act  simultane- 


BOtJNDARIKS    OF    THE    AXILLA.  3 

ously  ;  and  the  limb  will  be  luoved  forwards  or  backwards  in  accordance 
with  the  preponderating  power  of  the  pectoral  or  of  the  two  others. 
Their  action  may  occasion  dislocation  of  the  humerus  under  the  following 
circumstances.  In  falling,  with  the  arm  outstretched,  the  elbow  comes 
into  contact  with  the  ground,  and  renders  the  lower  end  of  the  humerus 
immovable  ;  and  if  the  muscles  then  act  suddenly  and  forcibly  they  will 
draw  down  the  upper  end  of  the  bone,  which  is  free  to  move,  and  bring 
it  into  tlic  axilla. 

The  serraius  magnus,  F,  shuts  out  the  ribs  from  the  axilla,  as  it  is 
directed  backwards  from  the  chest  to  the  scapula.  Its  separate  slips  of 
origin  from  the  ribs  (serrations)  are  marked  by  the  passage  between  them 
of  nerve.-,  and  here  and  there  of  small  vessels. 

The  subscapidaris,  H,  fills  the  hollow  of  the  scapula  and  excludes  this 
bone  from  the  ::xillc.  The  upward  and  outward  direction  of  its  fibres 
over  the  diouldor  ;"oint  is  indicated  in  the  Figure.  For  a  description  of 
the  muscle,  see  the  explanation  of  Plate  ii. 

The  ann.  muscles  are  the  coraco-brachialis,  K,  and  biceps,  L,  in  front 
of  the  liumorus,  and  the  triceps,  N,  behmd  that  bone.  The  share  taken 
by  the  two  last  muscles  in  the  outline  of  the  limb  may  be  seen  m  the 
Drawing  :  their  anatomy  will  be  studied  in  other  dissections. 

The  coraco-braclnalis,  K,  attached  as  the  name  expresses,  is  displayed 
fully  in  Plate  ii.  As  here  seen,  it  is  partly  subcutaneous,  and  lies  partly 
beneath  the  pectoralis  major.  The  swell  of  the  muscle  is  felt  readily 
through  the  teguments,  and  serves  as  the  surgeon's  guide  to  the  axillary 
artery  along  its  inner  edge, 

BOUNDAEIES  OF  THE  AXILLA. 

The  axilla  corresponds  with  the  surface  depression  of  the  arm-pit.  As 
it  is  a  portion  of  the  space  included  by  the  thoracic  muscles  converging 
to  the  humerus,  it  has  necessarily  a  pyramidal  form  ;  and  it  is  limited  in 
front  and  behind  chiefly  by  those  muscles,  whilst  inside  it  is  the  chest, 
and  on  the  outside  the  humerus.  This  intermuscular  interval  lodges  the 
large  vessels  and  nerves  of  the  limb,  with  lymphatics,  and  contains  a  loose 
granular  fat. 

Along  the  fore  part  lies  the  pectoralis  major,  A,  reaching  from  apex 
to  base,  and  forming  by  its  lower  or  free  edge  the  anterior  fold  of  the 
arm-pit;  and  underneath  it,  constructing  only  a  small  part  of  this  bound- 
ary, is  the  pectoralis  minor,  B.     After  the  fat  had  been  removed  from 


4  ILLDSTEATIONS    OF    DISSECTIONS. 

the  space,  the  pectoralis  sank  down  somewhat,  as  the  Drawing  indicates, 
in  consequence  of  the  body  not  being  very  fresh. 

Bounding  the  interval  behind  are  three  muscles,  viz.,  the  subscapu- 
laris,  H,  the  latissimus,  C,  and  the  teres  major,  D  :  the  two  latter  mus- 
cles enter  into  the  formation  of  the  lower  part  of  this  boundary,  and 
extend  lower  down  the  limb  than  the  pectoralis.  Within  the  edge  of  the 
latissimus,  here  shown  everted,  is  a  hollow  containing  vessels,  nerves, 
and  glands,  in  which  pus  may  burrow,  or  slightly  enlarged  glands  may 
lie  undetected  by  the  fingers. 

On  the  inner  convex  side  of  the  axilla  is  the  serratns  magnus,  F,  cov- 
ering the  four  highest  ribs  and  their  intercostal  muscles. 

On  the  outer  side,  where  the  space  is  limited,  are  placed  the  humerus 
and  the  contiguous  part  of  the  scapula,  with  the  coraco-brachialis,  K,  and 
biceps,  L,  muscles. 

The  base,  or  the  elongated  lower  opening  of  the  axilla,  is  wider  at  the 
chest  than  at  the  arm  ;  but  it  is  not  so  wide  before  as  after  the  dissec- 
tion, because  the  parts  when  cleaned  separate  from  each  other.  A  rather 
dense  fascia  closes  the  axillary  space  in  this  direction,  and  impedes  the 
advance  of  pus  to  the  surface. 

The  apex  or  narrowed  part  of  the  space  joins  the  root  of  the  neck,  and 
lies  between  the  chest  and  the  scapular  arch.  It  cannot  be  recognized 
in  this  Figure,  but  it  may  be  observed  more  completely  in  Plate  ii. 

The  state  of  the  muscular  boundaries  of  the  axilla  is  much  altered 
by  the  position  of  the  limb  ;  for  the  tenseness  is  diminished  when  the 
arm  is  adducted,  and  increased  when  the  arm  is  abducted  from  the  tho- 
rax. And  the  depth  will  vary,  m  like  manner,  with  change  in  the  posi- 
tion of  the  limb.  These  facts  may  be  remembered  with  advantage  in  any 
endeavor  to  estimate  the  size  of  the  tumor  in  the  axilla. 

In  consequence  of  the  position  of  this  intermuscular  space  at  the  in- 
ner side  of  the  shoulder  bone,  and  of  the  loose  nature  of  the  fatty  tissue 
contained  in  it,  the  movements  of  the  scapula  over  the  chest  are  facili- 
tated. And  from  its  situation  on  that  side  of  the  shoulder  joint  to  which 
flexion  is  made,  the  large  vessels  and  nerves  of  the  limb  are  transmitted 
through  it  beyond  the  joint  without  injury  from  stretching  in  the  motions 
of  that  articulation.  A  corresponding  hollow  exists  in  the  lower  limb  in 
front  of  the  hip-jomt. 

In  the  undissected  limb  the  student  may  recognize  by  the  eye  and  the 
touch  the  prominence  of  the  cords  of  the  large  axillary  nerves  and  ves- 


ARTERIES    OF    THE    AXILLA.  5 

sels  along  the  side  of  the  arm;  and  if  the  arm  is  raised  and  freely  moved 
by  one  hand,  whilst  the  two  fore  fingers  of  the  other  are  pressed  into  the 
arm-pit,  the  moving  head  of  the  humerus  may  be  felt  through  the  skin 
and  fascia.  During  life  the  hollow  is  useful  to  the  surgeon  in  his  at- 
tempts to  discover  the  nature  and  size  of  an  enlargement,  such  as  an 
aneurism,  in  this  situation,  or  the  position  of  the  dislocated  head  of  the 
humerus.  But  the  size  of  the  space  interferes  with  the  detection  of 
small  tumors,  like  an  enlarged  gland;  for  these  may  extend  upwards  and 
inwards  towards  the  chest  in  the  loose  fat,  and  acquire  considerable  size 
before  their  presence  will  be  indicated  by  any  external  swelling. 

ARTERIES  OF  THE  AXILLA. 

The  lower  end  of  the  axillary  artery  with  its  branches  are  now  brought 
under  notice  ;  but  only  a  small  narrow  strip  of  the  arterial  trunk  can  be 
seen  in  the  Figure  in  consequence  of  its  connections  with  veins  and  nerves 
being  preserved.  This  part  of  the  vessel  is  uncovered  by  muscle,  and  is 
in  contact  with  the  common  investing  parts  of  the  limb.  A  superficial 
wound  of  the  limb  may  lay  it  open.  It  supplies  branches  to  the  chest 
and  the  shoulder. 


a.  Axillary  artery. 
h.  Long  thoracic. 

d.  Alar  thoracic. 

e.  External  mammary. 
/.  Subscapxilar. 

g.  Dorsal  scapular. 


h.  Posterior  circumflex, 

n.  Cutaneous  artery  with  the  in- 
ternal cutaneous  of  the  musculo- 
spiral  nerve. 

o.  Artery  to  the  long  head  of  the 
triceps  muscle. 


The  axillari/  or  main  artery  of  the  upper  limb  crosses  the  space  from 
the  chest  to  the  arm  beneath  the  pectoral  muscles,  but  only  the  part  be- 
tween the  lower  border  of  the  pectoralis  major.  A,  and  the  lower  border 
of  the  teres  major,  D,  is  delineated.  Its  position  is  marked  by  the  swell 
of  the  coraco-brachialis  muscle,  K  ;  and  its  depth  from  the  surface  is 
very  slight,  only  the  tegumentary  coverings  of  the  limb  concealing  it,  so 
that  it  can  be  readily  reached  in  an  operation,  or  it  can  be  compressed 
with  ease  against  the  humerus. 

Its  connections  with  the  muscles  around  are  the  following  : — Behind 
are  the  subscapularis,  H,  the  latissimus,  C,  and  teres  major,  D ;  and  on 
the  outer  side  is  the  coraco-brachialis,  K. 

Its  companion   vein  (axillary)  is  placed  on  the  inner  or  chest  side. 


6  ILLUSTRATIONS    OF    DISSECTIONS. 

partly  concealing  the  artery,  and  has  to  be  drawn  aside  in  attempts  to  tie 
the  arterial  trunk. 

Large  nervous  cords  lie  around  the  artery : — outside  is  the  median  nerve, 
23  ;  inside  the  ulnar,  21,  and  the  nerve  of  Wrisberg,  11  (which  is  some- 
times nearer  the  artery).  Superficial  to  the  vessel  is  the  large  internal 
cutaneous,  18  ;  and  deeper  than  it  or  beneath,  is  the  musculo- spiral,  13 
(which  is  drawn  somewhat  inwards  below) ;  another  nerve  beneath  the 
artery  for  a  short  distance  is  the  circumflex,  12. 

Two  named  branches,  the  subscapular,  /,  and  the  posterior  circum- 
flex, h,  leave  this  part  of  the  artery  opposite  the  edge  of  the  subscapu- 
laris  muscle. 

Ligature  of  the  vessel.  The  origin  of  several  branches  from  the  axil- 
lary artery  opposite  the  shoulder  joint,  would  interfere  with  the  applica- 
tion of  a  ligature  at  that  spot ;  but  for  a  distance  of  two  inches  beyond 
(towards  the  arm)  the  vessel  is  free  from  any  large  branch,  and  might  be 
tied  without  risk  of  haemorrhage. 

Suitable  as  the  lower  part  of  the  axillary  trunk  seems  to  be  for  an 
operation  at  this  place,  surgeons  have  not  chosen  it  for  the  application  of 
a  ligature.  Doubtless  the  advantages  offered  by  tying  the  brachial  and 
subclavian  arteries  hp.ve  caused  those  vessels  to  be  selected  in  preference 
to  the  axillary  ;  but  the  small  channels  that  remain  for  the  collateral  cir- 
culation after  the  main  artery  is  secured  may  have  had  some  influence  in 
inducing  surgeons  to  let  the  operation  on  this  part  of  the  axillary  artery 
remain  unpractised.  For  the  only  collateral  vessels  to  carry  on  the  circu- 
lation after  the  occlusion  of  the  trunk  would  be  the  small  and  indirect 
anastomoses  through  the  following  muscles,  viz.,  the  coraco-brachialis, 
biceps,  and  long  head  of  the  triceps  ;  and  through  the  shaft  of  the 
humerus. 

Although  the  collateral  vessels  are  so  small  and  indirect,  they  are 
sufficient  for  carrying  on  the  circulation,  as  the  artery  has  been  tied  with 
success  in  this  situation.  M.  Blandin  secured  the  vessel  here  in  a  man 
who  received  an  injury  of  the  artery  from  the  discharge  of  a  gun.  The 
man  recovered.* 

Should  the  surgeon  be  called  upon  to  tie  the  artery  he  should  keep  in 
mind  its  situation  along  the  edge  of  the  coraco-brachialis,  with  its  com- 
panion vein  on  the  thoracic  side  and  partly  concealing  it,  and  with  large 

*  Traite  d'Anatomie  topographique,  p.  506  :  Paris,  1834, 


LIGATURE    OF   THE    AXILLARY    ARTERV.  7 

nerves  of  tlie  brachial  plexus  around  it.  Though  the  vessel  is  usually 
very  superficial,  it  may  be  placed  under  muscular  fibres  directed  over  it 
from  the  latissimus  to  the  pectoralis. 

Two  other  points  deserve  attention  also  :  Firstly,  that  two  arteries 
instead  of  one  may  be  found  as  often  as  1  in  10.*  Secondly,  that  not 
unfrequently  the  nerves,  which  should  serve  as  the  deep  guide  to  the 
artery,  arc  not  placed  around  the  parent  trunk,  but  encircle  a  laro-c  branch 
formed  by  the  conjunction  of  the  usual  offsets  at  this  spot  with  some  of 
the  branches  which  are  derived,  as  a  rule,  from  the  brachial  artery. 

When  practising  on  the  dead  body  the  tying  of  the  part  of  the  artery 

issuing  from  the  axilla  the  following  directions  may  be  observed  : 

The  limb  is  to  be  placed  at  right  angles  to  the  trunk,  and  the  operator 
stands  between  the  two. 

With  the  eye  fixed  on  the  prominence  of  the  coraco-brachialis  muscle, 
K,  which  is  the  superficial  guide  to  the  vessel,  a  cut  is  to  be  begun  in 
the  hollow  of  the  arm-pit,  and  to  be  continued  along  the  side  of  the 
muscle  for  two  inches  ;  but  the  knife  is  not  to  be  carried  deeper  at  first 
than  through  the  skin  and  fat. 

The  axillary  vein  will  now  be  recognized  through  the  deep  fascia  or 
aponeurosis  of  the  limb  by  its  blue  color  ;  and  the  aponeurosis  being- 
divided  along  the  outer  edge  of  the  vein  as  far  as  the  cut  in  the  integu- 
ments, this  vessel  may  be  detached  with  care  from  the  subjacent  parts, 
and  drawn  inwards  with  a  narrow  retractor. 

Next,  the  brachial  plexus  around  the  artery  will  serve  as  the  deep 
guide.  Search  is  to  be  made  for  the  axillary  trunk  by  cutting  a  piece  of 
fat  from  the  hollow  out  of  which  the  vein  has  been  drawn  ;  and  it  is  to 
be  made  in  a  horizontal  direction  or  towards  the  humerus,  instead  of 
backwards  towards  the  axillary  fold.  The  operator  tries  to  find  the  artery 
in  the  midst  of  the  nerve-trunks  without  attempting  to  distinguish  the 
individual  nerves. 

After  the  thin  arterial  sheath  has  been  opened  by  the  knife,  the  needle 
may  be  passed  readily,  and  the  vessel  is  to  be  tied  with  as  little  displace- 
ment as  possible. 

When  the  artery  is  not  surrounded  by  the  nerves  of  the  brachial  plexus, 

*  The  facts  on  which  this  statement  rests  will  be  found  in  the  Surgical  Anat- 
omy of  the  Arteries  of  the  Human  Body,  by  Richard  Quain,  F.R  S.  :  London, 

1844.  • 


8  ILLUSTRATIONS    OF    DISSECTIONS. 

as  referred  to  above,  ifc  will  be  nearer  the  vein  and  the  surface  than  it  is 
usnally. 

In  the  treatment  of  aneurism  of  the  lower  end  of  the  axillary  trunk 
Professor  Syme  l:as  recently  recommended  a  return  to  the  old  practice 
of  opening  the  sac,  and  after  removing  the  contents,  j)utting  a  thread 
around  the  vessel  above  and  below  the  sac.  In  a  jDostscrij^t  to  a  commu- 
nication published  in  the  Medico-Chirurgical  Transactions  *  he  says  : — 
"On  the  loth  of  August,  in  accordance  with  the  principles  above  ex- 
plained, I  performed  the  old  operation  for  aneurism,  not  traumatic,  at 
the  lower  part  of  the  axilla,  in  a  gentleman  about  fifty,  recommended  to 
my  care  by  Dr.  Embleton,  of  Embleton  in  Northumberland.  The  pa- 
tient returned  home  on  the  oth  of  September." 

Branches  of  the  artery.  The  lower  part  of  the  axillary  artery  sup- 
plies the  following  branches  to  the  wall  of  the  chest  and  the  shoulder. 

Long  thoracic  artery,  h,  lies  in  the  axilla  along  the  angle  formed  by 
;the  meeting  of  the  anterior  and  inner  boundaries,  and  may  be  injured  by 
a  cut  made  along  the  anterior  axillary  fold.  Its  origin  is  concealed  by 
the  pectoralis  major. 

Alar  thoracic  Ijranch,  cl.  This  small  artery  to  the  arm-pit  was  present 
in  this  body,  though  it  is  generally  absent  (Quain).  It  is  distributed  to 
some  of  the  glands,  and  to  the  fat  of  the  axilla. 

The  sulscaimlar  artery,  f,  is  the  largest  offset,  and  arises  opposite  the 
edge  of  the  subscapularis  muscle.  Taking  the  border  of  the  muscle  as 
its  guide,  it  reaches  the  chest,  to  which  and  the  shoulder  it  is  distributed. 
A  companion  vein  and  nerve  run  with  it,  and  all  are  secured  from  ex- 
ternal injury  by  the  projecting  margin  of  the  latissimus  dorsi.  Many 
•offsets  enter  glands  and  the  continguous  muscles-  and  one,  (j,  larger  than 
the  rest,  is  the  dorsal  scapular  artery. 

.  The  posterior  circumflex  artery,  //-,  arises  close  beyond  the  preceding, 
and  winds  behind  the  humerus  to  the  shoulder  with  the  nerve,  12,  of  the 
same  name.     Its  distribution  is  represented  in  Plato  v. 

An  anterior  circumflex  artery,  not  now  visible,  crosses  between  the 
humerus  and  the  coraco-brachialis  to  the  shoulder. 

The  external  mammary,  c,  is  a  long  slender  irregular  branch,  whicii 
is  directed  across  the  axilla  to  the  chest,  lying  about  midway  between  the 

*  On  the  Treatment  of  Axillary  Aneurism,  by  James  Syme,  F.R.S.  Edin.. 
vol,  43,  I),  143  :  London,  1860. 


.    VEINS    OF    THE    AXILLA.  d 

anterior  and  posterior  folds.  It  supplies  the  glands,  and  the  wall  of  the 
chest,  assisting  tlic  long  thoracic  artery. 

Muscular  and  cuUtncous  Irnnches. — Small  offsets  near  the  end  of  the 
artery  supply  the  coraco-brachialis,  K,  and  the  long  head  of  the  triceps, 
N.  And  a  cutaneous  tAvig,  n,  accompanies  the  internal  cutaneous  branch 
of  the  musculo-spiral  nerve. 

An  inspection  of  the  Drawing  will  suffice  for  showing  the  vessels  or 
nerves  likely  to  be  injured  in  Avounds  into  the  axilla,  or  in  incisions  made 
into  it  by  the  surgeon.  Along  the  anterior  boundaiy,  where  this  joins 
the  chest,  are  placed  the  long  thoracic  vessels;  and  lying  along  the  pos- 
terior boundary,  but  within  the  margin  of  the  latissimus,  are  the  sub- 
scapular vessels  and  nerves  Avith  glands.  On  the  side  of  the  limb,  or  at 
the  outer  part,  the  trunks  of  the  axillary  vessels  and  nerves,  and  the 
cords  of  the  brachial  plexus  are  aggregated  together;  whilst  on  the  side 
of  the  chest  there  is  only  an  occasional  small  artery.  If  an  incision  is  to 
be  made  into  the  arm-pit  the  surgeon  should  select  the  inner  boundary 
as  the  freest  from  vessels,  and  should  direct  the  knife  about  midway 
between  the  anterior  and  posterior  folds. 

VEINS    OF    THE    AXILLA. 

Only  the  position  of  the  chief  vein  to  the  artery  was  retained  in  the 
dissection;  and  the  smaller  veins,  which  would  complicate  the  drawing 
without  corresponding  utility,  were  removed. 


I.  Axillary  vein. 
tn.  Subscapular  vein. 


p.  External  niammarj'  vein. 
r.  Dutaneous  and  muscular  vein. 


The  axillary  vein,  I,  the  chief  trunk  of  the  limb,  is  continuous  in  the 
arm,  just  beyond  the  axilla,  with  the  cutaneous  vein — basilic.  Placed  on 
the  inner  or  thoracic  side  of,  and  jiartly  concealing  the  axillary  artery,  it 
receives  small  contributing  veins  corresponding  with  the  arterial  branches. 
Some  of  these  are  seen  in  the  Plate. 

Frequently  two  veins  instead  of  one  are  present  in  tiie  lower  part  of 
the  axillary  space. 

Through  this  vein  nearly  the  whole  of  the  blood  of  the  limb  below  , 
the  shoulder  is  conveyed  onwards;  and  interruption  to  its  current  will 
occasion  congesticri  in  the  parts  to  which  its  roots  extend.     A  tolerably 
complete  occlusion  of  this  main  circvdating  channel,  as  in  the  case  of  a 


10 


ILLUSTSATIONS    OF    DISSECTIONS, 


slowly-growing  tumor,  will  not  only  give  rise  to  congestion,  but  will 
cause  serous  fluid  to  transude  through  the  coats  of  the  vessels  into  the 
surrounding  textures. 


NERVES   OF   THE    AXILLA. 

The  nerves  in  this  dissection  are  derived  from  two  sources  : — Those 
on  the  side  of  the  chest  are  offsets  of  the  intercostal  nerves,  and  appear 
between  the  digitations  of  the  serratus  magnus  muscle;  and  those  lying 
around  or  near  the  axillary  vessels  belong  to  tlie  brachial  jolexus. 


Lateral  Cutaneous  of  the  1 

Thorax.  g 

1.  Lateral  cutaneous  branch  of    the  j       9. 

second     intercostal     nerve    (the  |     10. 

highest  of  the  set).  11' 

2.  Offset  of  third  intercostal.  12. 

3.  Offset  of  fourth  intercostal.  13. 

4.  Offset  of  fifth  intercostal.  14. 

5.  Offset  of  sixth  intercostal. 

6.  Anterior  branch  of  the  offset  of  tlie  |     16. 

second  intercostal.  ' 

■*** Anterior  branches  of  the  offsets  of  18. 

the  other  intercostal  nerves.  20. 

7.  Communicating    branch      to     the 

ner\-e  of  Wrisberg  from  the  offset  21. 

of  the  second  intercostal  nerve.  22. 


Brachial  Plexus. 

Nerve  to  the  teres  muscle. 

Subscapular  nerve. 

Nerv-e  to  the  serratus  magnus. 

Nerve  of  Wrisberg. 

Circumflex  nerve. 

Musculo-spiral. 

Offset  of  the  musculo-spiral  to  the 
triceps. 

Internal  cutaneous  of  the  musculo- 
spiral. 

Large  internal  cutaneous. 

Offset  of  the  internal  cutaneous 
to  the  integuments. 

Ulnar  nerve. 

Median  nerve. 


NERVES  OF  THE  BRACHIAL  PLEXUS. 

Tlie  median,  22,  is  the  companion  nerve  to  the  axillary  artery,  and  is 
placed  on  the  outer  side. 

The  uhia7'  nerve,  21,  smaller  than  the  median,  but  without  branch 
like  it,  lies  to  the  inner  side  of  the  arterial  trunk. 

The  vmsculo-spiral,  13,  occupies,  naturally,  a  position  beneath  the 
vessel,  but  it  has  been  pulled  inwards,  and  is  represented  in  the  Plate  as 
on  the  inner  side.  Here  it  furnishes  two  small  branches:  one  muscular, 
14,  to  the  inner  and  middle  heads  of  the  triceps;  the  other  is  the  in- 
ternal cutaneous,  16,  which  is  distributed  to  the  integuments  of  the  back 
of  the  arm. 


LATERAL   CUTANEOUS    NERVES    OF   THE   TIIORAX.  H 

The  circumflex  nerve,  13,  accompanies  the  artery  of  the  same  name, 
h,  to  the  deltoid  muscle.     See  Plate  v. 

Large  internal  cutaneous  nerve,  18,  lies  on  the  axillary  artery,  and 
gives  a  small  cutaneous  offset,  20,  to  the  integuments  of  the  arm  over  the 
situation  of  the  bloodvessels;  but  its  direction  has  been  altered  by  the 
displacement  of  the  skin. 

Small  internal  cutaneous  nerve,  11,  (nerve  of  Wrisberg)  issues  be- 
neath, though  sometimes  through  the  axillary  vein,  and  is  joined  by  a 
branch  7,  from  the  highest  lateral  cutaneous  nerve  of  the  thorax.  Its 
position  close  to  the  vein  has  been  disturbed  by  the  dragging  of  the 
skin. 

Muscular  branches.  The  nerve  to  the  teres  major,  8,  and  the  nerve 
to  the  latissimus,  9,  are  directed  with  the  subscapular  vessels  along  the 
back  of  the  arm-pit  to  their  destination;  the  former  gives  an  offset  to  the 
subscapularis  muscle. 

The  nerve  to  the  serratus  magnus  is  continued  on  the  surface  nearly 
to  the  lower  border  of  its  muscle,  giving  backwards  offsets  to  the  fleshy 
fibres.  Its  origin  is  connected  with  the  trunks  of  the  fifth  and  sixth  cer- 
vical nerves  in  the  neck. 

Pressure  applied  to  the  nerves  of  the  brachial  plexus  may  occasion 
pain,  or  loss  of  power  and  feeling,  according  to  its  degree,  in  a  greater 
or  smaller  part  of  the  limb.  In  the  use  of  crutches  the  weight  of  the 
body  acts  injuriously  on  the  nerves,  for  the  arm  is  arched  over  the  top  of 
the  crutch,  and  the  nerves  are  compressed  between  the  humerus  and  the 
artificial  jjrop  of  the  body.  This  inconvenience  may  be  remedied  by  the 
crutch-head  being  so  constructed  as  to  bear  least  on  the  centre  of  the 
arm  over  the  large  nerves. 

LATERAL  CUTANEOUS   NERVES  OF  THE    THORAX. 

Five  lateral  cutaneous  branches  of  the  intercostal  trunks  were  laid 
bare  in  the  dissection;  they  appear  lax  after  they  have  been  separated 
from  the  surrounding  fat.  The  branches  directed  forwards  over  the  pec- 
toralis  v^ere  necessarily  detached  from  the  skin,  and  were  then  laid  on 
the  surface  of  the  muscle. 

As  the  first  intercostal  trunk  does  not  furnish  commonly  any  lateral 
cutaneous  branch,  the  nerves  sliOAvn  are  derived  from  the  five  next  inter- 
costal trunks.     Each  branch  divides  into  two  parts  (anterior  and  poste- 


12  ILLUSTRATIONS    OF   DISSECTIONS. 

nor)  as  it  issues  between  the  ribs,  and  these  terminate  on  the  lateral  part 
of  the  thorax. 

The  anterior  offsets,  6,  *  *  *,  end  in  the  integuments  covering  the 
pectoralis  major;  and  the  posterior,  1,  2,  3,  4,  5,  somewhat  larger  in 
•size,  ramify  in  the  skin  of  the  arm,  and  in  that  over  the  latissimus  dorsi. 
In  this  body  the  third  nerve  wanted  an  anterior  offset. 

The  highest  and  largest  of  the  lateral  cutaneous  nerves, — that  from 
the  second  intercostal  trunk,  differs  in  some  respects  from  the  others. 
Its  anterior  branch,  G  (laid  on  the  pectoralis,  and  not  always  present), 
supplies  the  arm-pit  as  well  as  the  teguments  on  the  pectoralis  major-  its 
posterior  branch,  1,  called  intercosto-humeral,  reaches  the  integuments 
of  the  back  of  the  arm,  and  gives  a  communicating  offset,  7,  to  the 
nerve  of  Wrisberg. 

LYMPHATICS   OF  THE  AXILLA. 

Only  a  few  of  the  glands  of  the  axilla  were  retained  in  the  dissection, 
and  these  have  fallen,  necessarily,  from  their  natural  position  after  the 
removal  of  the  fat  in  which  they  are  imbedded. 


f  f  f  Anterior  group  of  the  axillary 

glands. 
s  s  s.  Posterior  group  of  glands. 


t.  One  of  the  group  of  glands  along 
the  side  of  the  axillary  vessels. 


About  ten  or  twelve  in  number,  the  glands  vary  much  in  their  shape 
and  size.  They  have  the  following  general  linear  arrangement  in  sets. 
The  greater  or  hinder  gi'oup  lies  along  the  subscapular  vessels  within  the 
edge  of  the  latissimus  dorsi;  but  after  the  dissection  of  the  axilla  they 
hang  in  front  of  the'  muscle  by  their  small  vessels,  as  is  shown  in  the 
Plate.  Another  or  anterior  group  is  nearer  the  fore  part  of  the  axilla,  in 
connection  with  the  long  thoracic  and  external  mammary  arteries.  And 
a  third  set  is  placed  along  the  large  axillary  vessels. 

Each  collection  of  glands  has  for  the  most  part  its  own  set  of  lym- 
phatic vessels.  Thus  the  anterior  group  receives  lymphatics  from  the 
fore  part  of  the  thorax  and  from  the  mamma:  the  posterior  group  is 
oined  by  the  lymphatics  from  the  side  of  the  chest,  and  from  the  back; 
and  that  along  the  bloodvessels  transmits  lympathics  from  the  upper 
limb.  The  lymphatic  vessels,  after  passing  through  their  respective 
glands,  unite  into  one  or  more  trunks  at  the  top  of  the  axilla,  and  open 
into  the  lymphatic  duct  of  the  same  sida 


.    FAT    IN    THE    AXILLA.  13 

Disease  in  the  part  from  which  the  lymphatic  vessels  are  derived  may 
occasion  enlargement  of  the  group  of  glands  through  which  those  ves- 
sels are  transmitted;  and  the  knowledge  of  the  destination  of  the  lym- 
phatics will  suggest  the  glandular  group  likely  to  be  affected: — Thus,  a 
poisoned  wound  of  the  hand,  as  in  dissection,  Avill  cause  inflammation  of 
the  glands  by  the  side  of  the  axillary  vessels;  and  so  forth. 

In  making  the  necessary  examination  to  detect  disease  of  the  glands, 
the  limb  should  be  approximated  to  the  side  to  relax  the  muscles  and 
fascia  bounding  the  axilla,  and  thus  to  permit  easier  and  freer  manipula- 
tion. The  glands  near  the  axillary  vessels  follow  the  arm  when  this  is 
elevated. ' 

Enlargement  of  a  gland  may  surround  or  press  upon  the  intercosto- 
humeral  nerve,  or  the  nerve  of  Wrisberg,  and  occasion  numbness  in  the 
part  to  which  either  nerve  is  distributed. 

Should  extirpation  of  a  diseased  gland  be  considered  advisable,  the 
surgeon  should  be  mindful  that  it  has  large  bloodvessels,  in  the  form  of  a 
foot-stalk,  which  are  derived  from  the  contiguous  vessels;  and  he  should 
secure  the  vascular  pedicle  with  a  thread  before  he  cuts  it  through.  If 
this  precaution  is  neglected  the  divided  vessels  retract  into  the  loose  are- 
olar tissue  of  the  axilla,  and  may  continue  to  bleed  at  intervals  so  as  to 
endanger  life. 

FAT  IN  THE  AXILLA. 

The  axilla  is  filled  with  a  granular  fat  intermixed  with  slight  areolar 
tissue.  Towards  the  apex  of  the  space  the  adipose  tissue  diminishes.  In 
thin  bodies  the  quantity  of  the  fat  is  less,  as  it  is  in  all  other  parts,  and 
the  space  contains  a  watery  fluid  in  the  meshes  of  the  areolar  tissue. 

The  presence  of  fat  favors  in  this  space,  as  elsewhere,  the  accumula- 
tion of  pus,  which  burrows  amongst  the  loose  fatty  material  instead  of 
making  its  way  to  the  surface  through  the  intervening  fascia.  Much  in- 
convenience and  suffering  may  Be  avoided  by  an  early  incision  for  the 
escape  of  the  confined  pus. 


14  ILLUSTKATIONS    OF    DISSECTIONS. 


DESCPtlFTION  OF  PLATE  II. 


The  Figure  represents  the  deep  dissection  of  the  front  of  the  chest, 
and  that  of  the  axillary  vessels  and  the  brachial  plexus  of  nerves  with 
their  branches. 

The  dissection  is  to  be  made  by  cutting  through  and  reflecting  the 
pectoralis  major.  To  render  tense  and  distinct  the  sheath  of  the  axillary 
vessels,  place  the  limb  at  right  angles  to  the  trunk,  and  rotating  it  in- 
wards, press  it  backwards,  so  as  to  raise  the  clavicle  from  the  chest. 
Unless  this  position  of  the  arm  is  kept,  the  loose  costo-coracoid  sheath 
may  be  removed  with  the  fat. 

SUPERFICIAL  PROMINENCES  OF  BONE. 

At  the  upper  part  of  the  region  dissected  is  the  bony  loop  of  the 
scapular  arch,  which  is  formed  by  the  clavicle,  J,  and  the  scapula,  and 
separates  the  neck  from  the  chest  and  the  limb.  It  serves  the  purpose 
of  articulating  the  upper  limb,  and  furnishes  points  of  attachment  to 
muscles  moving  the  humerus.  Injury  of  the  arch,  sufficient  to  break  it, 
will  arrest  the  free  movements  of  the  shoulder  joint,  and  interfere  with 
the  action  of  the  muscles. 

Part  of  the  arch  is  subcutaneous,  and  the  forefinger  when  carried 
along  it  traces  successively  the  outline  of  the  clavicle,  acromion,  and 
sjjine  of  the  scapula.  From  its  slight  depth  injuries  of  it  are  easily  as- 
certained, because  all  irregularity  of  the  surface  can  be  detected  at  once 
with  the  finger. 

On  the  inner  side  of  the  shoulder  joint  below  the  clavicle,  and  pro- 
jecting at  the  edge  of  the  deltoid  muscle,  E,  is  the  coracoid  process.  It 
gives  attachment  to  the  three  muscles  B,  K,  and  L,  as  well  as  to  a  strong 
ligament  (coraco-clavicular),  which  passes  from  its  upper  and  hinder 
part  to  the  under  surface  of  the  clavicle,  and  unites  together  firmly  the 
two  bones.  On  the  surface  of  the  body  this  projecting  osseous  point  can 
be  felt  between  the  deltoid  and  pectoral  muscles. 

In  consequence  of  the  clavicle  acting  as  a  prop  to  keep  the  shoulder 


PLATL 


-li. 


^ 

^ 


^^^ 

"m^ 


t 


SCAPULAR    ARCH.  15 

from  the  trunk,  it  is  very  liable  to  be  broken.  By  direct  violence  it 
may  be  shattered  at  any  spot;  but  force  applied  to  the  outer  end 
through  a  fall  or  a  blow  produces  fracture  generally  about  the  middle  of 
the  bone. 

In  fracture  of  the  shaft,  that  is,  internal  to  the  line  of  the  coracoid 
process  and  the  strong  ligament  joining  this  part  to  the  clavicle,  the 
scapula  and  shoulder  joint,  having  lost  their  support,  fall  downwards  and 
inwards  towards  the  chest,  forcing  the  outer  past  the  inner  fragment; 
and  the  large  muscles  of  the  chest  which  are  inserted  into  the  humerus 
assist  in  bringing  the  shoulder  into  closer  apposition  with  the  thorax. 
The  inner  fragment,  freed  from  the  weight  of  the  shoulder,  remains  in 
its  natural  position,  though  it  appears  more  than  usually  prominent;  and 
the  muscles  attached  on  opposite  sides,  viz.,  the  great  pectoral  and  sterno- 
mastoid,  may  act  also  as  antagonists,  and  prevent  its  displacement. 

If  the  fracture  takes  place  opposite  the  strong  ligament  uniting  the 
coracoid  process  with  the  clavicle,  the  scapula  remains  attached  to  the 
clavicle  by  that  ligament,  though  not  perfectly  supported  by  it,  and  the 
shoulder  falls  but  little  towards  the  chest. 

In  fracture  external  to  the  ligament,  there  is,  however,  considerable 
displacement  of  the  bone,  for  the  outer  detached  end  being  loose,  and 
being  acted  on  by  the  trapezius  muscle,  is  placed  in  front  of,  and  may 
take  even  a  position  at  a  right  angle  to  the  other.* 

In  replacing  the  external  fragment  of  a  broken  shaft  ol  the  clavicle, 
the  piece  of  bone  must  be  moved  outwards  indirectly  by  forcing  out- 
wards the  scapula;  and  it  is  to  be  raised  to  the  level  of  the  inner  frag- 
ment by  lifting  and  supporting  the  elbow. 

At  the  outer  part  of  the  dissection  is  the  projection  of  the  shoulder, 
which  is  produced  by  the  upper  end  of  the  arm  bone  covered  by  the 
deltoid  muscle,  E.  When  the  limb  is  pendent  the  swell  of  the  muscle 
runs  into  that  of  the  arch  formed  by  the  clavicle  and  acromion;  and 
when  the  limb  is  raised  and  lowered,  the  arm  bone  can  be  felt  moving 
under  the  muscle. 

In  dislocation  of  the  shoulder  joint  the  upper  end  of  the  humerus 
sinks  down  from  the  deltoid;  and  a  hollow  then  occupies  the  site  of  the 
prominence.     This  injury  is  accompanied  necessarily  by  unnatural  direc- 

*  A  Treatise  on  Fractures  in  the  Vicinity  of  Joints,  by  Robert  William.  Smith, 
M.D.:  Dublin,  1850;  p.  210. 


16 


ILLUSTRATIONS    OF    DISSECTIONS. 


tion  of  the  shaft  of  the  arm  bone  forwards  or  backwards,  and  by  a  sharp 
edge  along  the  bony  arch  of  the  clavicle  and  the  acromion  jDrocess. 


MUSCLES  OF  THE  THORAX  AND  ARM. 


A.  Pectoralis  major. 

B.  Pectoralis  minor. 

C.  Latissimus  dorsi. 

D.  Teres  major. 

F.  Serratus  magnus. 
H.  Subscapularis. 

J.  Clavicle  with  the  cut  attachment 
of  the  pectoralis  major. 


K.  Coraco-brachialis. 

L.  Biceps,  its  short  head. 

O.  Biceps,  the  long  head. 

N.  Triceps  extensor  brachii, 

P.  Insertion  of  pectoralis  major. 

R.  Deltoid  muscle. 

Si  Subclavius  muscle. 

V.  Costo-coracoid  membrane. 


The  muscles  of  the  chest  and  shoulder,  which  are  partly  displayed  in 
the  Drawing,  give  to  the  scapula  and  the  shoulder  joint  some  of  their 
varied  movements. 

The  scapula  has  a  gliding  motion  over  the  ribs,  and  can  be  moved  in 
opposite  directions.  It  is  drawn  forwards  by  the  small  pectoral,  B,  and 
serratus  magnus  muscle,  F,  which  attach  it  to  the  chest. 

The  shoulder  being  a  ball  and  socket  joint  is  provided  with  muscles 
on  opposite  sides;  but  only  two  are  now  evident,  viz.,  the  deltoid  or 
great  abductor,  R,  and  the  subscapularis  or  internal  rotator,  H. 

In  the  group  of  thoracic  muscles  are  included  the  pectoralis  major 
and  minor,  the  serratus  magnus,  the  latissimus  dorsi,  and  the  subclavius. 

Pectoralis  major,  A.  After  the  division  of  the  muscle  the  parts 
underneath  it  can  be  observed.  It  covers  the  pectoralis  minor  on  the 
chest,  and  the  coraco-brachialis,  K,  and  the  biceps,  L  and  0,  in  the  arm. 
Near  the  clavicle  the  subclavius  muscle,  S,  and  the  costo-coracoid  mem- 
brane, V,  lie  beneath  it.  Above  and  below  the  pectoralis  minor  the  ax- 
illary vessels  and  nerves  are  covered  by  the  great  pectoral  muscle  alone. 

At  its  insertion  the  tendon  is  divided  into  two  parts,  with  an  interval 
between,  something  like  a  sling.  On  the  under  piece,  P,  the  lower 
chest  fibres  are  received;  and  in  the  other  (seen  only  in  part),  the  upper 
thoracic  and  the  clavicular  fibres  terminate. 

The  pectoralis  minor,  B,  is  attached  to  the  side  of  the  chest,  and  to 
the  third,  fourth,  and  fifth  ribs;  it  is  inserted  externally  into  the  coracoid 
process  of  the  scapula,  where  it  blends  in  a  common  tfindon  with  the 
coraco-brachialis,  K,  and  the  short  head  of  the  biceps,  L. 


MUSCLES' OF    THE    THORAX    AND    ARM.  17 

Between  tl»e  chest  and  the  shoulder  tlie  muscle  forms  part  of  the 
anterior  l)oundary  of  the  axilla,  and  lies  over  the  axillary  vessels  and 
nerves;  and  between  the  muscle  and  the  clavicle  is  a  triangular  interval 
— the  sides  being  formed  by  that  bone  and  the  pectoralis  minor,  the  base 
by  the  thorax,  and  the  apex  by  the  coracoid  process — in  which  the  upper 
part  of  the  axillary  artery  may  be  tied.  Its  position  to  other  vessels  and 
nerves  is  so  aj)parent  as  not  to  need  farther  notice. 

The  pectoralis  minor  assists  the  serratus,  as  before  said,  in  drawino- 
forwards  the  scapula;  and  it  may  act  as  a  muscle  of  forced  insj)iration 
when  the  scapula  is  the  fixed  j)art. 

Serratus  magnus,  F,  covers  the  side  of  the  chest,  taking  origin  bv 
nine  fleshy  slips  from  the  eight  upper  ribs;  and  it  is  inserted  into  the 
base  of  the  scapula.  Its  special  nerve,  5,  lies  on  the  surface,  and  distri- 
butes offsets  to  it. 

From  the  direction  of  its  fibres  the  muscle  is  chiefly  employed  in 
moving  forwards  the  scapula  over  the  ribs;  and,  when  the  scapula  is 
fixed,  it  will  act  on  the  ribs  so  as  to  draw  them  outwards,  and  increase 
the  size  of  the  chest  in  inspiration.  It  supports,  too,  the  lower  end  of 
the  scapula  whilst  a  weight  is  carried  on  the  shoulder. 

Latissimiis  dorsi,  C.  The  oblique  direction  of  this  muscle  behind 
the  axilla,  converging  with  the  pectoralis  major  to  the  insertion  into 
the  humerus,  is  more  fully  seen  in  this  than  in  the  preceding  dissec- 
tion. The  chief  notice  of  this  muscle  is  given  with  the  explanation  of 
Plate  i. 

Subdavius,  S.  This  small  muscle  is  contained  in  a  sheath  of  the 
costo-coracoid  membrane,  of  which  a  piece  has  been  cut  away  near  the 
inner  end.  Named  from  the  position  to  the  clavicle,  its  origin  is  at- 
tached to  the  first  rib,  and  its  insertion  is  fixed  into  the  grooved  under 
surface  of  the  clavicle. 

It  can  depress  the  clavicle  or  elevate  the  first  rib,  according  as  the 
one  or  the  other  bone  may  be  in  a  state  to  be  moved. 

The  shoulder  muscles  coming  into  view  in  this  dissection  are,  the 
subscapularis,  teres  major,  and  deltoid. 

The  subscapularis,  H,  arises  from  the  hollowed  costal  surface  of  the 
scapula,  and  its  fibres  are  directed  outwards  and  upwards  over  the  shoul- 
der joint  to  their  insertion  into  the  small  tuberosity  and  the  neck  of  the 
humerus. 

By  its  lower  edge  it  projects  much  beyond  the  scapula,  and  touches 

9, 


18  ILLUSTRATIONS    OF   DISSECTIONS. 

the  latissimus  dorsi  and  teres  major.     The  subscapularis  supports  inter- 
nally the  shoulder  joint,  of  which  it  is  one  of  the  articular  muscles. 

When  the  arm  is  raised,  the  subscapularis  assists  in  depressing  it;  and 
the  hanging  limb  is  rotated  inwards  by  the  muscle. 

This  muscle  is  injured  in  the  following  dislocations  of  the  humerus. 
When  the  bone  is  forced  into  the  lower  part  of  the  axilla,  it  may  either 
be  covered  by  the  subscapularis;  or  may  be  driven  through  the  muscular 
fibres,  and,  coming  into  contact  with,  press  upon  the  mass  of  the  axillary 
vessels  and  nerves.  In  the  forward  dislocation  on  the  inner  side  of  the 
cervix  of  the  scapula,  the  head  of  the  bone  passes  between  the  subscapu- 
laris and  the  scapula,  separating  the  fleshy  fibres  from  the  blade-bone, 
and  projects  above  the  uj^per  border  of  the  muscle.* 

Teres  major,  D.  Only  the  general  position  of  the  teres,  which  ex- 
tends from  the  lower  angle  and  border  of  the  scapula  to  the  humerus, 
can  be  now  seen.     The  muscle  is  described  with  Plate  v. ,  D. 

The  deltoid  muscle,  R,  forms  the  prominence  of  the  shoulder,  and 
reaches  from  the  scapular  arch  to  the  arm  bone  below  the  level  of  the 
axilla.  Only  the  fore  part  of  the  muscle  is  here  represented:  its  inser- 
tion and  connections  are  seen  in  Plate  v.,  N. 

Three  muscles  of  the  arm,  biceps,  coraco-brachialis,  and  triceps,  are 
laid  bare  in  the  dissection — the  two  former,  which  are  superficial  to  the 
humerus,  being  much  more  apparent  than  the  latter,  which  is  behind 
the  bone.  The  anatomy  of  the  triceps  will  be  given  in  the  notice  of 
Plate  vi. 

The  Mceps  muscle  consists  above  (origin)  of  two  parts,  long  head  and 
short  head. 

The  short  head,  L,  is  fixed  by  a  wide  tendon  to  the  coracoid  process; 
and  the  long  tendinous  head,  0,  narrow  and  rounded,  passes  along  the 
groove  in  the  humerus,  and  through  the  shoulder  joint,  to  be  attached 
to  the  top  of  the  glenoid  articular  surface  of  the  scapula. 

The  muscle  is  shown  lower  in  the  arm  in  Plate  iv. 

Coraco-hracliialis,  K.  It  arises  from  the  coracoid  process  of  the 
scapula,  and  the  tendon  of  the  short  head  of  the  biceps;  and  it  is  inserted 
into  the  inner  side  of  the  shaft  of  the  humerus  about  midway  between 

*  The  student  will  find  the  state  of  the  muscles  in  dislocations  of  the  shoulder 
joint  fully  treated  in  the  article,  Abnormal  Conditions  of  the  Shoulder  Joint,  in 
the  Cyclopcedia  of  Anatomy  and  Physiology,  by  Robert  Adams,  Esq.,  1849. 


ARTERIES    OF    THE    AXILLA. 


19 


tlie  ends.  Its  upper  extremity  lies  beneath  the  pectoralis  major;  its 
insertion  is  concealed  by  the  brachial  vessels;  and  the  intermediate  part 
(belly)  is  subcutaneous  in  the  arm-pit,  and  serves  as  the  guide  to  the 
axillary  vessels.  Through  the  fleshy  fibres  of  the  muscle  the  musculo- 
cutaneous nerve,  11,  is  transmitted. 

If  the  limb  is  in  a  state  of  abduction,  it  can  be  brought  to  the  side  of 
the  chest  by  this  muscle. 

The  costo-coracoid  membrane,  V,  is  a  rather  strong  layer  of  fascia 
between  the  upper  limb  and  the  neck,  and  is  placed  there  apparently  for 
the  purpose  of  protecting  the  large  blood-vessels.  Occupying  the  hiterval 
between  the  first  rib  and  the  coracoid  process,  it  is  fixed  above  to  the 
clavicle  before  and  behind  the  subclavius  muscle  which  it  incases.  Below 
it  blends  with  the  special  sheath  (axillary)  of  the  blood-vessels,  giving  to 
this  additional  strength  ;  and  it  is  continued  onwards  beneath  the  small 
pectoral  muscle,  where  it  gradually  ceases. 

The  axillary  sheath  around  the  vessels  and  nerves  coming  from  the 
neck  to  the  upper  limb,  consists  in  part  of  a  prolongation  from  the  deep 
fascia  of  the  neck,  and  in  part  of  a  stronger  layer  added  from  the  costo- 
coracoid  membrane.  It  resembles  the  crural  sheath  around  the  blood- 
vessels of  the  lower  limb,  and  is  funnel-shaped  like  that  tube.  In  it  are 
the  axillary  artery  and  vein,  and  the  brachial  plexus  ;  and  piercing  the 
front  are  branches  of  those  trunks,  viz.,  the  cephalic  vein,  ?,  the  acromial 
thoracic  artery,  c,  and  anterior  thoracic  nerves,  3,  3.  In  a  dissection  of 
the  axillary  sheath  the  tube  is  to  be  opened  in  the  manner  shown  in  the 
drawing,  to  see  the  position  to  each  other  of  the  contained  bloodvessels 
and  the  brachial  plexus  of  nerves. 

ARTERIES  OF  THE  AXILLA. 

The  connections  of  the  trunk  of  the  axillary  artery,  and  the  distribu- 
tion of  most  of  its  branches,  can  be  studied  in  Plate  ii. 


a.  Axillary  arteiy. 

h.  Superior  thoracic  branch. 

c.  Acromial  thoracic  branch. 

d.  Long  tlioracic  branch. 


e.  External  mammary  branch. 

/.  Subscapular  branch. 

g.  Dorsal  branch  of  the  subscapular. 


The  axillary  artery,  a,  crosses  from  the  chest  to  the  arm  through  the 
axilla  ;  and  is  limited  above  by  the  lower  border  of  the  subclavius  muscle. 


20  ILLUSTRATIONS    OF    DISSECTIONS. 

S,  and  below  by  tlie  lower  edge  of  the  teres  major,  D.  Without  dissec- 
tion, the  situation  of  the  vessel  may  be  indicated  by  a  line,  on  the  surface 
of  the  body,  from  a  point  of  the  clavicle  somewhat  on  the  sternal  side  of 
the  middle  of  the  bone,  to  the  inner  border  of  the  coraco-brachialis 
muscle,  K. 

In  a  dissection  carried  no  farther  than  the  one  from  which  the  draw- 
ing is  taken,  the  artery  is  divided  into  three  parts  by  the  pectoralis 
minor,  B,  viz.,  one  part  above,  one  beneath,  and  one  beyond  the  muscle. 
The  upper  or  first  part  lies  in  the  axillary  sheath  between,  but  deeper 
than  its  companion  vein  and  nerves.  Superficial  to  the  sheath  is  the 
clavicular  attachment  of  the  great  pectoral  muscle  ;  and  underneath  it  is 
the  side  of  tlie  chest  with  the  intercostal  muscles  of  the  first  space,  and 
the  serratus  magnus,  F. 

Crossing  the  artery,  are  some  small  branches  of  the  companion  vein 
and  nerves  ; — thus  directed  over  it  from  the  'outer  side  is  the  cephalic 
vein,  I,  and  an  anterior  thoracic  nerve,  3  ;  and  passing  under  it  is  the 
nerve  to  the  serratus,  5. 

Second  part.  Here  the  artery  is  covered  by  both  pectoral  muscles, 
large  and  small ;  but  it  is  without  muscular  support  behind  in  conse- 
quence of  its  position  across  the  axilla. 

The  large  axillary  vein,  li,  has  the  same  relative  position  to  this  as  to 
the  first  part ;  whilst  the  brachial  plexus,  1,  dividing  into  pieces,  is  so 
arranged  that  one  bundle  lies  outside,  another  inside,  and  a  third  behind 
the  vessel. 

The  tliird  part,  twice  as  long  as  either  of  the  others,  is  in  contact  for 
two  thirds  of  its  lengtli  with  tlie  pectoralis  major,  but  thence  to  the  end- 
ing it  is  covered  only  by  the  common  tegumentary  structures.  It  rests 
successively  from  above  down  on  the  subscapularis,  H,  the  latissimus 
dorsi,  C,  and  the  teres  major,  D.  To  its  outer  side  lies  the  coraco- 
brachialis  muscle,  K. 

The  position  of  the  companion  vein  remains  the  same  as  above  ;  but 
the  connections  of  the  nerves  are  altered,  for  the  brachial  plexus  has 
divided  into  its  terminal  branches,  which  are  j)laced  on  opposite  sides  of 
the  vessel.  Outside  are  two  nerves,  the  musculo-cutaneous,  11,  reaching 
only  a  short  distance  ;  and  the  median,  12,  Avhich  extends  throughout. 
Inside  is  the  ulnar  nerve,  13  (here  somewhat  displaced) ;  and  more  or 
less  removed  from  the  artery,  is  the  small  internal  cutaneous  nerve,  9. 
Superficial  to  the  artery  is  the  large  internal  cutaneous,  14  ;  and  beneath 


LIGATURE    OF    THE    AXILLARY.  21 

but  concealed  by  it,  the  circumflex  and  musculo-spiral  nerves — the  formei 
reaching-  only  to  the  edge  of  the  subscapularis  muscle. 

Numhcr  and ijosition  of  tlie  arterial  offsets.  Branches  are  distributed 
internally  to  the  thorax,  and  externally  to  the  shoulder  and  arm. 

From  the  first  part  come  two  offsets,  the  highest  thoracic,  l,  and 
acromial  thoracic,  c  ;  the  first  is  small  and  irregular  in  its  size  and  posi- 
tion ;  and  the  latter,  much  larger,  springs  close  to  the  edge  of  the 
pectoralis. 

Only  occasionally  is  there  any  named  branch  on  the  second  part. 

Four  or  five  branches  spring  from  the  third  part  of  the  parent  trunk. 
The  first  of  these,  long  thoracic,  d,  is  close  to  the  border  of  the  pectoralis 
minor.  The  next  or  subscapular  branch  arises  opposite  the  loAver  border 
of  the  subscapularis  muscle.  Two  circumflex  arteries  take  origin  near 
the  last,  but  they  arc  concealed  by  the  trunks  of  the  axillary  vessels.  The 
last-named  branch  given  off  is  the  small  external  mammary,  e. 

Ligature  of  the  artery. — The  axillary  artery  may  be  tied  near  the 
clavicle,  as  ■well  as  near  the  ending  (p.  G). 

Near  the  clavicle,  or  above  the  small  pectoral  muscle,  the  vessel  lies 
deeply,  and  is  reached  only  after  cutting  through  the  pectoralis  major. 
Two  offsets,  superior  and  acromial  thoracic,  spring  usually  from  this  part 
of  the  artery,  wath  the  supra-scapular  (a  branch  of  the  subclavian)  some- 
times, and  they  leave  scarcely  interval  enough  for  the  application  of  a 
ligature,  especially  if  the  first  is  large.  The  connections  also  of  the 
artery  with  superficial  vessels  and  nerves  are  so  complicated  (see  Plate)  as 
to  render  hazardous  ligature  of  it  at  this  s]3ot. 

The  vessel  might  be  tied  in  this  situation  for  aneurism  of  the  lower 
2?art  of  the  arterial  trunk,  or  for  the  arrest  of  hemorrhage  after  an  opera- 
tion high  up  the  arm  ;  but  the  difficulties  in  securing  the  vessel,  and  the 
chances  of  recurring  bleeding,  may  almost  deter  a  surgeon  from  having 
recourse  to  the  operation. 

Should  it  be  necessary  to  ligature  the  artery  here,  a  practical  knowl- 
edge of  the  anatomy  will  assist  the  operator  in  his  attem2:)ts  to  secure 
the  vessel. 

With  the  arm  outstretched,  the  position  of  the  artery  Avill  be  marked 
by  a  line  over  the  surface  of  the  pectoralis  major,  which  has  been 
described  already  (p.  20). 

Tho  surface  depressions  on  the  sides  of  the  clavicular  attachment  of 
the  pectoralis  major  being  taken  as  the  limit  of  the  incisions,  the  operator 


22  ILLUSTRATIONS    OF    DISSECTIONS. 

divides  by  a  transverse  cut  near  the  clavicle  the  integuments  and  the  thin 
platysma  muscle,  and  afterwards  the  clavicular  part  of  the  pectoralis, 
looking  for  the  cephalic  vein  at  the  outer  edge  of  the  muscle.  "When  the 
thick  fleshy  fibres  of  the  pectoral  muscle  are  cut  tlirough,  the  subjacent 
fat  with  small  veins,  arteries,  and  nerves,  ramifying  in  it,  will  appear. 
With  much  caution  the  surgeon  finds  his  Avay  amidst  these  dangers  to 
the  axillary  sheath,  V,  which  he  opens  to  the  necessary  extent. 

In  the  bottom  of  the  v/ound  the  firm  white  brachial  plexus  of  nerves 
will  conduct  now  to  the  artery  deeply  placed  between,  and  overlapped  by 
the  nerves  and  the  axillary  vein.  The  artery  will  be  recognized  by  its 
joulsation,  feel,  and  color ;  and  when  it  is  detached  from  the  contiguous 
parts,  the  operator  may  enter  the  aneurism  needle  between  the  vein  and 
artery,  so  that  the  point  of  the  instrument  may  be  directed  towards  the 
nerves  as  it  turns  under  the  arterial  trunk. 

Aneurism  of  the  upper  part  of  the  axillary  artery  is  a  formidable 
disease.  It  may  be  confined  to  the  axilla,  enlarging  forwards  and  back- 
wards where  there  is  least  resistance,  or  it  may  jiass  the  bounds  of  that 
space,  and  project  above  the  clavicle  into  the  neck.  As  long  as  the  dis- 
ease is  low  on  the  vessel,  and  is  confined  to  the  axilla,  ligature  of  the 
end  of  the  subclavian  artery  has  been  resorted  to  in  its  treatment.  But 
when  it  rises  above  the  collar-bone,  and  the  subclavian  operation  is 
rendered  unsuitable  or  impracticable,  surgeons  have  sometimes  had  re- 
course to  the  extreme  measure  of  amputating  the  limb  at  the  shoulder- 
joint,  as  there  "seemed  to  be  no  alternative,"  to  use  the  Avords  of 
Professor  Syme. 

In  the  last-mentioned  class  of  cases,  which  are  so  embarrassing  to 
treat.  Professor  Syme  recommends,  that  the  aneurism  should  be  laid  open, 
and  the  contents  removed,  as  in  the  old  plan  of  operating  on  blood- 
tumors.  From  the  result  of  two  cases  treated  successfully  in  this  way, 
he  hopes  that  "axillary  aneurism  not  amenable  to  ligature  of  the  sub- 
clavian artery  may  be  remedied  by  the  old  operation  ; "  and  he  thinks 
that,  even  in  cases  where  ligature  of  the  subclavian  is  2:>racticable,  the 
plan  recommended  may  be  preferable.* 

Branches  oftlie-ariery.  All  the  branches  are  distributed  to  the  chest 
and  the  shoulder,  and  maintain  the  circulation  in  the  limb  when  the 


■■  See  a  Paper,  before  referred  to,  on  the  Treatment  of  Aneurism,  in  the  Medico- 
Chirurgical  Transactions  of  London  for  1860. 


ARTERIES    OF    THE    AXILLA.  23 

parent  vessel  has  been  obliterated.  The  number  of  the  named  branches 
has  been  estimated  differently  by  anatomists  in  consequence  of  their  irreg- 
ularity. 

The  highest  thoracic,  h,  is  the  smallest  branch,  and  ends  on  the  top  of 
the  chest,  above  the  pectoralis  minor. 

The  acromial  thoracic,  c  (humeral  thoracic,  thoracic  axis?),  supplies 
three  sets  of  offsets,  viz.,  external  or  acromial,  internal  or  thoracic,  and 
middle  or  ascending.  The  outer  set  enters  the  deltoid  muscle;  the 
inner  set  is  furnished  to  both  pectoral  muscles,  a  few  twigs  reaching  the 
side  of  the  chest;  and  the  middle  set  courses  over  the  axillary  sheath  to 
the  subclavius,  and  the  pectoral  and  deltoid  muscles. 

The  long  thoracic  branch,  d,  arises  opposite  the  lower  border  of  the 
small  pectoral  muscle,  and  courses  along  it  to  the  fifth  or  sixth  intercostal 
space,  where  it  ends  in  the  surrounding  parts,  and  communicates  with  the 
intercostal  arteries.     In  the  female,  it  supplies  the  breast. 

The  subscapular,  f,  a  large  branch,  passes  along  the  muscle  of  the  same 
name  to  the  inferior  angle  of  the  scapula,  and  is  distributed  by  large 
branches  to  the  contiguous  muscles,  serratus  and  latissimus,  anastomos- 
ing in  the  first  with  the  intercostals. 

Kear  its  beginning,  the  dorsal  scapular  branch,  g,  leaves  it  to  supply 
the  opposite  surfaces  of  the  scapula.     See  Plate  v. 

Two  circumflex  arteries  encircle  the  humerus,  meeting  on  the  outer 
side.     Plate  v.  may  be  looked  to  for  a  delineation  of  them. 

Other  muscular  offsets  (not  marked  by  letters  of  reference)  enter  the 
coraco-brachialis  muscle. 

Two  occasional  branches  are  noticed  below,  viz.,  the  alar  thoracic  and 
external  mammary. 

Alar  thoracic.  This  belongs  to  the  glands  in  the  axilla,  and  is  sel- 
dom to  be  found  as  a  distinct  branch  (Quain) :  offsets  to  the  glands  are 
generally  supplied  by  the  subscajiular.  Plate  i.  If  the  alar  thoracic 
exists  as  a  separate  artery,  it  may  spring  from  the  second  or  the  third 
part  of  the  axillary  trunk. 

The  external  mammary ,  e,  appears  to  be  a  compensating  branch  to 
the  long  thoracic,  d,  both  supplying  like  parts.  It  begins  near  the  ter- 
mination of  the  axillary  trunk,  and  is  accompanied  by  a  vein,  m. 

Anastomosis  of  the  branches.  The  blood  finds  it  way  from  one  part 
of  the  body  to  another  through  the  communications  of  the  smaller  ves- 
sels, though  its  flow  in  the  main  trunk  is  obstructed,  and  the  anastomoses 


24:  ILLUSTRATIONS    OF    DISSECTIONS. 

of  the  branches  of  the  axillary  artery  with  those  of  the  neck  and  chest, 
by  which  the  collateral  circulation  would  be  established  after  ligature  of 
the  axillary  artery,  will  be  now  considered. 

On  the  chest,  the  thoracic  offsets  of  the  upper  thoracic,  acromial  and 
long  thoracic,  external  mammary  and  subscapular  branches  anastomose 
with  the  intercostal  and  internal  mammary  arteries. 

On  the  shoulder,  the  branches  of  the  axillary  communicate  with  two 
branches  of  the  subclavian  trunk,  viz.,  the  posterior  scapular  and  supra- 
scapular. Offsets  of  the  subscapular  artery,  distributed  to  both  surfaces 
of  the  scapular,  join  both  the  above-mentioned  subclavian  branches. 
Other  anastomoses  take  place  with  the  supra- scapular  in  the  following 
way:  through  the  deltoid  muscle  offsets  of  the  acromial,  thoracic,  dorsal 
scapular,  and  posterior  circumflex  communicate  with  that  artery,  and 
through  the  capsule  of  the  shoulder-joint,  the  anterior  and  posterior  cir- 
cumflex unite  with  it. 

VEINS   IN   THE   AXILLA. 

All  the  smaller  companion  veins  which  would  interfere  with  the  view 
of  the  arteries  and  nerves  have  been  taken  away. 


h.  Axillaiy  vein. 
k.  Brachial  vein. 


I.  Cephalic  vein. 
m.  External  mammary. 


The  axillary  vein,  h,  has  the  same  extent  as  the  artery  by  whose  side 
it  lies,  and  is  continuous  in  the  limb  with  the  superficial  vein  called 
basilic.  Plate  iii.  Throughout  its  length  it  maintains  the  same  posi- 
tion Avith  regard  to  the  artery,  i.  e.,  on  the  thoracic  side,  and  it  has  simi- 
lar connections  with  the  parts  around.  Below  the  pectoralis  minor  the 
vein  is  often  double,  and  above  that  muscle  it  has  been  once  found 
divided  (Morgagni). 

Contributing  small  veins,  corresponding  with  the  branches  of  the 
artery,  enter  it  at  intervals;  it  receives  besides  near  the  lower  border  of 
the  subscapularis  muscle  a  trunk,  k,  formed  by  the  brachial  veins,  and 
near  the  clavicle,  the  superficial  vein  of  the  arm — cephalic,  I. 

The  cephalic  vein,  I,  ascending  over  the  shoulder  between  the  pecto- 
ral and  deltoid  muscles,  sinks  through  the  fascia  of  the  limb,  and  passing 
under  the  great  pectoral,  pierces  the  axillary  sheath  to  reach  its  destina- 
tion.    Its  position  to  the  axillary  artery  has  been  specially  described. 


NKRVES    IN    THE    AXILLA. 


25 


NERVES  IN   THE   AXILLA. 


With  the  exception  of  one  lateral  cutaneous  nerve  of  the  thorax,  all 
the  nerves  here  represented  are  derived  from  the  brachial  plexus. 


1.  Brachial  plexus. 

2.  Thoracic  ofifsets  of  the  plexus. 

5.  Nerve  to  the  serratus  magnus. 

6.  Nerve  to  the  latissimus. 

8.  Lateral  cutaneous  of  the  second 

intercostal. 

9.  Small  internal  cutaneous. 


10.  Nerve  to  tlie  teres  major. 

11.  Musculo-cutaneous  nerve. 

12.  Median  nerve. 

13.  Ulnar  nerve. 

14.  Large   internal  cutaneous  of  the 

arm. 


The  brachial  plexus  of  nerves,  1,  furnishes  offsets  to  the  chest, 
shoulder,  and  arm.  Placed  on  the  outer  side  of  the  first  part  of  the 
artery,  it  surrounds  the  second  part  with  its  large  trunks,  and  terminates 
in  branches  for  the  arm,  which  lie  around  the  third  part  of  that  vessel. 
The  following  are  its  offsets  to  muscles  bounding  the  axilla.- 

Anterior  thoracic  nerves  are  tAvo  or  three  in  number.  Two,  2,  3, 
come  from  the  outer  part,  and  one,  4,  from  the  inner  part  of  the  plexus, 
and  supply  the  pectoral  muscles;  the  small  pectoral  receives  its  offsets 
at  the  under  surface  from  the  nerve  marked  4. 

Nerve  to  the  serratus  magjius,  5,  comes  from  the  plexus  above  the  clavi- 
cle, and  may  be  seen  ramifying  m  its  muscle. 

Nerve  to  the  latissiinns  dorsi,  6,  enters  opjoosite  the  axilla  the  under 
surface  of  its  muscle. 

The  nerve  to  the  teres  major  and  subscapular  is,  10,  belongs  specially 
to  the  first  muscle,  giving  only  a  small  piece  to  tlie  latter,  for  the 
subscapularis  is  supplied  higher  up  in  the  axilla  by  an  offsect  of  the 
plexus. 

The  remaining  branches  of  the  brachial  plexus  are  continued  to  the 
upper  limb,  viz. : 

The  S7nall  internal  cutaneous,  9  (nerve  of  Wrisberg),  communicates 
in  the  axilla  with  the  second  intercostal  nerve,  8. 

The  musculo-cutaneous,  11,  pierces  the  coraco-brachialis.  The  me- 
dian, 12,  the  ulnar,  13,  and  the  large  internal  cutaneous,  14,  lie  by  the 
side  of  the  axillary  artery,  and  will  be  traced  afterwards  m  the  limb.     Tlie 


26  ILLUSTRATIONS    OF    DISSECTIONS. 

remaining  two  branches  of  the  plexus,  circumflex  and  musculo-spiral,  are 
concealed  by  the  great  axillary  vessels. 

Remarks  on  the  plexus. — A  tumor  in  the  axilla  compressing  any  of  the 
surrounding  nerves  may  occasion  pain  or  dulness  of  feeling,  according  to 
the  degree  of  injury,  in  the  part  to  which  the  nerve  or  nerves  affected  by 
it  may  be  distributed. 

In  dislocation  downwards  of  the  humerus  into  the  arm-pit,  the  head 
of  the  bone  pressing  on  the  nerves  which  lie  along  its  inner  side,  occasions 
the  pain  or  numbness  in  the  limb. 

In  the  flap  amputation  of  the  shoulder-joint,  the  large  vessels  and 
nerves  are  cut  last,  as  the  knife  forms  the  flap  on  the  inner  side,  and  the 
nerves,  not  contracting  after  division  like  the  other  structures,  reach  to 
the  end  of  the  flap,  and  may  be  involved  in  the  cicatrix  left  after  the 
wound  is  healed  if  they  are  not  cut  shorter. 

One  lateral  cutaneous  nerve  of  the  thorax,  8,  has  been  left  to  show  its 
connections  with  the  nerve  of  Wrisberg,  9.  Sending  a  communicating 
offset  to  this  nerve  in  the  axilla,  it  is  continued  onwards  to  the  integu- 
ments of  the  arm  as  the  intercosto-humeral. 


LYMPHATIC  GLANDS  IN  THE  AXILLA. 

One  of  the  highest  of  the  group  of  lymphatic  glands  by  the  side  of 
the  axillary  vessels  is  shown  in  position  on  the  side  of  the  chest.  Two 
small  lymphatic  vessels  ascend  from  it,  and  pierce  the  inner  side  of  the 
axillary  sheath  to  join  the  deep  lymphatics  of  the  neck. 


PLATE 


N  i 
^ 


BICEPS    MU8CLE    AND    THE    FASCIA    OF    THE    ARM. 


27 


DESCRIPTION  OF  PLATE  III. 


A  DISSECTION"  of  the  superficial  veins  and  nerves  in  front  of  the  bend 
of  the  elbow  is  represented  in  this  Plate,  for  the  purpose  of  illustrating 
the  operation  of  blood-letting. 

For  the  dissection  a  longitudinal  incision  was  carried  over  the  middle 
of  the  joint,  and  was  limited  by  a  transverse  cut  at  each  end.  On  reflect- 
ing the  two  flaps  of  skin,  the  subcutaneous  vessels  and  nerves  will  be 
found  in  the  fat.  A  piece  of  the  deep  fascia  should  be  raised,  as  may  be 
seen  in  the  drawing,  to  show  the  position  of  the  deep  artery  and  nerve. 


BICEPS  MUSCLE  AND  THE  FASCIA  OF  THE  ARM. 

The  deep  fascia  of  the  limb  deserves  special  attention,  as  it  is  the  only 
protecting  layer  between  the  cutaneous  veins  and  the  main  artery  of  the 
arm. 


A.  Biceps  muscle. 

B.  Deep   or    special    fascia    of  the 

arm. 

C.  Piece  of    the    deep    fascia    re- 

flected. 


D.  Inner  intermuscular  septum. 

F.  Projection  of  the  inner  condyle 

of  the  humerus. 
I.  Intermuscular  space  on  the  front 

of  the  forearm. 


Biceps  muscle,  A.  At  its  lower  end  the  muscle  diminishes  in  size, 
and  becoming  tendinous,  is  fixed  into  the  radius.  Higher  in  the  arm  it 
gives  rise  to  the  well-known  prominence,  with  a  groove  or  hollow  on 
each  side  lodging  the  superficial  veins  of  the  arm,  viz.,  the  basilic,  li,  on 
the  inside,  and  the  cephalic,  h,  on  the  outside.  The  swell  of  the  mus- 
cle serves  as  a  guide  to  the  brachial  artery  along  its  inner  edge. 

The  deep  fascia,  or  the  aponeurosis  of  the  limb,  invests  closely  the 
arm,  and  is  pierced  here  and  there  by  the  nerves  and  vessels  of  the  integ-  , 
uments.     Its  component   fibres  take   different  directions,    some  bemg 
transverse,  others  oblique;  and  it  is  joined  at  spots  by  offsets  from  the 
tendons  of  tho  muscles.     One  such  offset,  added  to  it  from  the  tendon  of 


28 


ILLUSTRATIONS    OF    DISSECTIONS. 


the  biceps  in  front  of  the  bend  of  the  elbow,  gives  it  increased  strength 
between  the  deep  artery,  I,  and  the  superficial  median  basilic  vein,  g. 

On  each  side  of  the  arm  is  a  thickened  part,  which  is  fixed  to  the 
humerus  between  the  flexor  and  extensor  muscles,  and  is  called  inter- 
muscular septum:  these  processes  are  attached  to  the  condyloid  ridges 
of  the  bone  ;  and  the  inner  one,  best  developed,  is  marked  by  the  letter 
D. 

Near  the  bend  of  the  elbow,  where  the  piece  of  the  fascia  is  reflected, 
the  contiguity  of  the  underlying  brachial  artery  may  be  observed. 

The  fascia  is  prolonged  over  the  muscles  to  the  forearm  ;  and  appear- 
ing through  it  below  tlie  elbow  is  a  well-marked  yellow  line,  I,  pointing 
to  an  intermuscular  space  which  contains  the  upper  end  of  the  radial 
vessels. 

Straightening  the  elbow-Joint  increases,  and  bending  the  joint  relaxes 
the  tightness  of  the  fascia.  So  the  pain  consequent  on  tension  of  the 
fascia  from  accumulation  of  blood  or  other  fluid  beneath  it,  or  from 
swelling  of  the  parts  inclosed  by  it,  may  be  relieved  by  placing  the  limb 
in  a  bent  position. 


SUPERFICIAL  VEINS  OF  THE  ELBOW. 


Great  irregularity  prevails  in  the  arrangement  of  the  superficial  veins 
in  front  of  the  elbow.  The  condition  of  them  depicted  in  the  Plate  is 
not  quite  usual,  though  it  is  sufficiently  regular  for  the  purpose  of  describ- 
ing their  anatomy. 


a.  Median  vein  of  the  forearm. 

h.  Anterior  ulnar  veins. 

e.  Posterior  ulnar  veins. 

d.  Radial  vein  of  the  forearm. 


/.  Median  cephalic  vein. 
g.  Median  basilic  vein. 
h.  Basilic  vein  of  the  arm. 
h.  Cephalic  vein  of  the  arm. 


The  median  vein,  a,  lies  along  the  middle  of  the  forearm,  and  divides 
near  the  bend  of  the  elbow  into  two,  viz.,  an  outer,  the  median  cephalic 
vein,/;  and  an  inner,  the  median  basilic  vein,  g,  into  which  the  other 
veins  of  the  forearm  open.  At  its  ending  the  median  communicates 
with  a  deep  vein  through  the  fascia. 

Anterior  and  posterior  idnar  veins,  h,  and  c,  gather  the  blood  from 
•the.  opposite  surfaces  of  the  inner  half  of  the  forearm,  and  both  join  the 


SUPERFICIAL    VEINS    OF    THE    ELBOW.  29 

median  basilic,^, — the  anterior  ulnar  entering  about  the  middle,  .and  the 
l)osterior  ulnar  at  the  ending  of  that  vein. 

The  radial  vein,  d,  ramifies  on  the  back,  and  outer  part  of  the  fore- 
arm, and  opens  into  the  end  of  the  median  cephalic,  /.  Oftentimes  this 
vein  is  very  small ;  or  it  may  be  wanting. 

The  median  ceiilialic  vein,  f,  reaches  from  the  point  of  splitting  of 
the  median,  a,  to  the  outer  border  of  the  limb,  where  it  unites  with  the 
radial,  d,  and  forms  the  large  cephalic  vein,  h.  It  crosses  the  limb  ob- 
liquely in  the  hollow  between  the  prominent  biceps  and  the  external 
muscles  of  the  forearm.  Underneath  it -lies  the  large  external  cutaneous 
nerve,  3,  and  over  it  pass  some  offsets  of  the  same  nerve.  Generally  this 
vein  is  the  smallest  of  the  two  pieces  into  which  the  median  divides,  and 
is  sometimes  absent. 

A  moderately  tight  bandage  round  the  limb  just  above  the  elbow,  as 
in  the  operation  of  bleeding,  does  not  stop  the  flow  of  blood  in  the  median 
cephalic  vein  in  a  muscular  arm  in  consequence  of  the  projection  of  the 
biceps  arresting  the  pressure  of  the  band.  But  the  current  of  blood  in 
the  vessel  may  be  commanded  by  the  thumb  inserted  into  the  hollow 
outside  the  biceps,  and  pressed  downwards  steadily. 

The  median  basilic  vein,  g,  is  directed  inwards  from  the  median  vein, 
a  ;  and  uniting  with  the  joosterior  ulnar  veins,  c,  gives  rise  to  the  basilic 
vein,  A.  Usually  longer  and  larger  than  the  median  cephalic,  it  is  com- 
monly more  transverse  in  its  direction,  and  is  firmly  supported  by  the 
subjacent  fascia  and  muscle.  Joining  it  below  are  the  anterior  ulnar 
veins.  The  chief  branches  of  the  large  internal  cutaneous  nerve,  1,  lie 
under,  and  smaller  offsets  over  the  vein  ;  but  in  this  dissection  the  main 
part  of  the  nerve  was  superficial  to  the  vein.  In  the  line  of  the  yellow 
space,  I,  under  the  fascia,  the  brachial  artery,  /,  crosses  underneath  the 
median  basilic  vein,  the  two  being  separated  only  by  the  aponeurosis  of 
the  limb  somewhat  thickened  by  the  prolongation  from  the  tendon  of  the 
biceps. 

The  vein  being  well  supported  underneath,  the  current  of  blood  in  it 
can  be  readily  stopped  by  the  thumb  or  finger,  or  by  a  band  round  the 
arm  above  the  elbow  compressing  the  basilic  vein. 

The  basilic  vein,  U,  begins  at  the  point  of  union  of  median  basilic,  g, 
with  the  posterior  ulnar  veins,  c.  Ascending  through  the  lower  part  of 
the  arm  in  the  groove  or  depression  inside  the  biceps,  it  sinks  under  the 
fascia  half  way  up  the  arm,  and  becomes  the  axillary  vein. 


30  ILLUSTRATIONS    OF    DISSECTIONS. 

The  cejjhalic  vein  of  the  arm,  Ic,  formed,  as  before  said,  by  the  junc- 
tion of  the  median  cephalic,  /,  with  the  radial  vein,  d,  continues  on  the 
outer  side  of  the  biceps  as  far  as  the  shoulder,  and  ends  in  the  axillary 
vein.     See  Plate  ii.,  /. 

Blood-letting  is  practised  commonly  in  the  veins  in  front  of  the  elbow. 
Either  the  median  basilic,  ^,  or  the  median  cephalic,/,  is  selected  for 
venesection  according  to  its  size  ;  and  the  median  basilic  is  most  fre- 
quently opened  in  consequence  of  its  being  the  largest,  and  on  account 
of  the  readiness  v/ith  which  it  may  be  fixed  and  compressed  against  the 
firm  supporting  parts  beneath.  If  the  operation  is  to  be  performed  by 
the  student  for  the  first  time,  the  following  directions  may  be  of  use. 

To  stop  the  flow  of  blood  in  the  superficial  veins,  a  narrow  band  or 
fillet  is  to  be  tied  around  the  arm  from  two  to  three  inches  above  the 
elbow.  This  band  should  not  be  drawn  too  tightly,  as  moderate  pres- 
sure will  arrest  the  current  of  blood  in  the  veins  ;  and  too  great  tight- 
ness will  compress  the  brachial  artery  in  thin  j)ersons,  and  prevent  the 
free  entrance  of  the  blood  into  the  limb  below  the  elbow.  After  the 
bandage  has  been  applied,  the  state  of  the  arteries  should  be  examined, 
to  ascertain  that  the  pulse  beats  with  the  same  force  and  frequency  as  in 
the  other  arm  ;  for  if  the  pressure  diminishes  the  current  of  blood  in  the 
main  artery,  a  full  stream  will  not  be  maintained  through  the  opening 
;made  into  the  vein. 

Supposing  the  median  basilic  vein,  g,  to  be  selected  for  venesection, 
the  position  of  the  brachial  artery  is  to  be  ascertained  by  the  jDulsation, 
and  the  vein  is  not  to  be  ojDened  directly  over  the  beating  artery.  After 
this  examination  the  operator  stands  on  the  inner  side  of  the  limb  and 
grasps  the  forearm  near  the  elbow  with  his  hand,  placing  the  thumb  in 
front;  and,  using  his  left  hand  for  the  right  arm,  and  the  opposite,  he 
will  hold  the  lancet  in  the  left  hand  when  taking  blood  from  the  left 
limb.  With  slight  pressure  of  the  thumb  the  vein  is  now  to  be  fixed  ; 
and  if  this  step  is  omitted,  the  point  of  the  lancet  only  punctures  and 
pushes  aside  the  full  and  freely  movable  vein.  The  aperture  into  this 
vessel  is  to  be  made  close  to  the  thumb,  both  the  skin  and  the  vein-wall 
being  divided  obliquely  to  the  same  extent ;  and  it  should  be  large 
enough  to  prevent  the  blood  clotting,  and  closing  it  too  soon.  To  give 
the  necessary  size  (about  a  quarter  of  an  inch)  the  lancet  is  first  to  be 
pushed  downwards,  and  is  next  to  be  made  cut  its  way  to  the  surface,  in 
order  that  the  structures  may  be  divided  from  within  out ;  for  if  the 


BLOODLETTING    AT   TIIK    ELBOW.  31 

point  of  the  instrument  is  thrust  in  and  drawn  out,  making  a  punctured 
wound,  only  a  very  small  quantity  of  blood  will  flow  through  the  open- 
ing before  this  is  narrowed  or  stopped  by  coagulating  blood.  As  the 
walls  of  the  vein  are  approximated  by  the  compression  of  the  thumb,  too 
deep  an  incision  of  the  lancet  may  cut  through  the  vein,  causing  effu- 
sion of  blood  beneath  with  resulting  obstruction  to  the  issuing  current ; 
and  the  operation  may  be  accompanied  by  puncture  of  the  subjacent 
brachial  artery. 

The  operator  does  not  relinquish  his  hold  of  the  arm  and  his  control 
of  the  vein  (for  only  a  few  drops  of  blood  will  escape  till  the  thumb  is 
removed)  until  he  has  had  time  to  put  his  lancet  aAvay,  and  bring  the 
receiving  basin  into  the  proper  position.  After  instructing  the  person 
being  bled,  not  to  move  the  arm  Avith  the  view  of  trying  to  direct  the 
jet  of  flowing  blood,  he  takes  his  thumb  off  the  vein,  and  allows  the 
blood  to  issue  in  a  full  stream,  though  he  still  supports  the  limb  with  his 
own  hand.  Leaving  the  control  of  the  liniD  to  the  patient,  as  when  a 
stick  is  grasped  by  the  hand,  will  oftentimes  cause  the  flow  of  blood  to 
cease;  because  in  his  attempts  to  direct  the  current  of  blood  into  the 
basin  he  alters  the  position  of  the  arm,  and  the  opening  in  the  vein  is 
closed  by  the  skin  being  brought  over  it. 

Should  the  displacement  of  the  skin  take  place,  the  blood  accumulates 
under  it,  forming  a  tumor  called  'Hhrombus,"  and  compresses  the  vein. 

When  sufficient  blood  has  been  obtained  the  thumb  is  to  be  jDlaced  on 
the  vein,  as  before,  close  below  the  opening,  for  the  purpose  of  stopping 
the  bleeding,  and  the  bandage  is  to  be  loosened.  A  small  compress  of 
linen,  made  ready  before  the  operation  is  begun,  is  to  be  placed  on  the 
wound  ;  and  is  to  be  fixed  in  position  by  the  fillet  applied  like  a  figure 
of  8  around  the  elbow  whilst  the  limb  is  slightly  bent.  Slight  pressure 
of  the  bandage,  a  half  bent  state  of  the  elbow,  and  rest,  are  most  condu- 
cive to  the  healing  of  the  wound. 

If  the  median  cephalic,  f,  should  be  selected  for  venesection  in  conse- 
quence of  its  greater  size,  the  steps  to  be  taken  in  the  operation  are  the 
same  as  those  above  referred  to,  with  the  exception  of  the  manner  in  which 
the  current  of  blood  in  it  is  to  be  checked.  Tying  up  the  limb  in  the 
usual  way  will  scarcely  make  pressure  enough  upon  the  median  cephalic 
in  a  muscular  arm,  because  the  vein  sinks  into  the  hollow  on  the  side  of 
the  biceps.  A  more  effectual  compression  may  be  exerted  by  sinking  the 
thumb  in  the  groove  between  the  biceps  and  supinator  longus  muscles  ; 


32  ILLUSTRATIONS    OF    DISSECTIONS. 

or  if  a  fillet  is  used,  by  inserting  under  it  a  small  compress  over  the  situ- 
ation of  the  vein.  In  consequence  of  its  position  in  a  hollow,  the  vein 
may  be  rather  more  difficult  to  reach  with  the  lancet,  especially  in  a  fat 
person. 

From  the  position  of  the  brachial  artery  under  the  median  basilic 
vein  puncture  of  it  may  take  place  in  the  operation  of  bleeding.  This 
serious  accident  is  occasioned  by  cutting  the  vein  directly  over  the  artery, 
and  pushing  the  lancet  too  deeply  after  transfixing  the  vein.  Injury  of 
another  artery  may  ensue,  under  the  following  circumstances.  One  of 
the  large  arteries  of  the  forearm  (radial  or  ulnar)  may  arise  higher  in  the 
arm  than  usual,  and  in  passing  the  elbow  to  its  destination,  may  lie 
sujoerficially — being  placed  generally  under  the  aponeurosis  of  the  limb, 
but  sometimes  in  the  fat,  by  the  side  of  the  veins.*  When  it  is  con- 
tained in  the  integuments,  its  projection  in  a  fat  arm  might  be  taken  for 
the  swell  of  a  vein  on  an  insufficient  examination.  The  occasional  exist- 
ence of  such  a  state  of  the  arteries  should  lead  to  a  careful  examination 
of  the  front  of  the  elbow  before  venesection,  with  a  view  of  detecting 
pulsation  not  only  in  the  brachial  trunk,  but  also  in  any  other  unusually 
placed  artery. 

Injury  of  an  artery  in  blood-letting  would  be  manifested  by  the  blood 
being  redder  than  ordinary  venous  blood;  by  the  fluid  escaping  in  jerks  ; 
and  by  pressure  on  the  vein  below  the  opening  not  stopping  the  bleeding. 
Such  an  untoward  accident  should  be  met  by  placing  a  conical  compress 
on  the  wound  ;  and  by  applying  a  bandage  firmly  along  the  limb  with 
the  intention  of  preventing  the  escape  of  the  blood,  and  its  accumulation 
under  the  deep  fascia. 

As  the  wound  in  the  artery  does  not  heal  readily,  like  that  in  the 
skin  and  the  vein  for  instanac,  a  blood-tumor  or  aneurism  usually  follows. 
Into  this  tumor  the  blood  passes  through  the  hole  in  the  artery,  and  it  is 
inclosed  in  a  sac  formed  by  the  surrounding  parts  (false  aneurism). 

Or  the  wound  in  the  back  of  the  vein  not  healing,  a  permanent  com- 
munication with  the  artery  is  established,  through  which  the  arterial 
blood  is  driven  into  the  vein,  2:)roducing  distention,  and  a  varicose  con- 
dition of  the  superficial  veins  below  the  elbow.  If  the  edges  of  the  con- 
tiguous openings  in  the  vessels  unite  without  the  intervention  of  any  sac, 
so  that  the  vein  receives  blood  directly  from  the  artery,  the  term  aneu- 

"■•■  Surgical  Anatomy  of  the  Arteries,  by  Professor  Quain. 


ANEDEISM    AFTKE   BLEEDING.  33 

rismal  varix  is  applied  to  that  condition  of  the  parts.  If,  on  the  con- 
trary, a  sac  or  tumor  is  formed  between  the  artery  and  vein,  which 
communicates  with  both,  and  serves  as  a  channel  by  which  the  arterial 
current  can  pass  into  the  vein,  the  aneurism  is  called  varicose. 

For  the  treatment  of  a  blood  tumor  or  aneurism  formed  after  bleed- 
ing, Avhether  it  opens  only  into  the  artery  (traumatic  false  aneurism)  or 
joins  both  the  artery  and  the  vein  (varicose  aneurism),  an  operation  on 
the  brachial  artery  will  be  needed  if  its  enlargement  cannot  be  controlled 
bv  pressure.  And  the  operation  suited  for  the  cure  of  the  disease  would 
be  that  of  opening  the  tumor,  and  applying  a  ligature  above  and  below  the 
wound  in  the  artery.  If  the  tumor  is  somewhat  solidified  by  the  deposi- 
tion of  laminated  fibrin  in  it,  ligatui-e  of  the  brachial  artery  in  the  mid- 
dle third  of  the  arm  would  be  had  recourse  to  by  some  surgeons.  But 
the  safer  practice  seems  to  consist  in  tying  the  vessel  at  the  wounded 
part  as  a  rule  ;  and  this  treatment  would  be  most  suitable  also  for  aneu- 
rism connected  with  a  wound  of  the  radial  or  the  ulnar  artery  in  conse- 
quence of  its  unusual  origin,  and  its  superficial  position  in  the  fat  in  front 
of  the  elbow.  Professor  Syme  advocates  cutting  down  upon  the  tumor 
in  aneurism  from  a  wound  of  the  brachial  in  front  of  the  elbow.  He 
says  :  "  I  have  treated  all  the  aneurisms  at  the  bend  of  the  arm,  resultino- 
from  wound  of  the  humeral  artery  through  venesection,  which  have 
come  under  my  care,  amounting  to  ten  in  number,  by  opening  the  sac, 
and  applying  ligatures  on  both  sides  of  the  aperture.  "* 

In  the  aneurismal  varix  equable  pressure  on  the  limb,  wliich  will 
check  the  arterial  blood  entering  the  tube  of  the  vein  to  any  great  extent, 
may  do  away  with  the  necessity  of  any  aperative  proceeding.  Should 
the  disease  be  a  source  of  suffering,  and  interfere  with  the  use  of  the 
arm,  as  in  a  laboring  man  for  example,  it  may  be  readily  cured  by  liga- 
ture of  the  artery  at  the  part  wounded. 

In  venesection  puncture  of  a  nerve  will  sometimes  cause  great  pain. 
In  the  Plate  several  branches  of  the  internal  cutaneous  nerve  cross  the 
median  basilic  vein,  and  any  of  these  might  be  injured  ;  but  as  their 
position  cannot  be  ascertained  during  life,  no  precaution  can  be  taken  to 
avoid  them.     Commonly  the  puncture  occasions  only  pain  at  the  time  of 


*  The  Paper  on  the  Treatment  of  Aneurism  before  referred  to.     Medico-Chir- 
urgical  Transactions,  1860. 
3 


34  ILLUSTRATIONS    OF    DISSECTIONS. 

bleeding,  though  in  some  conditions  of  the  body  it  may  give  origin  to 
serious  general  disturbance  of  the  health. 

Inflammation  of  the  vein  or  phlebitis  may  result  from  bleeding ;  it 
will  require  the  treatment  appropriate  to  that  affection. 

Several  other  diseased  states  produced  by  venesection,  with  their  treat- 
ment, were  described  by  Abernethy;  and  the  student  who  is  desirous  of 
obtaining  further  information  may  look  to  the  essays  of  that  surgeon.* 

The  student  should  observe  scrupulously  the  injunction — never  to 
bleed  with  a  lancet  that  has  been  used  for  other  purj)oses. 

BRACHIAL  ARTERY  AT  THE  ELBOW. 

The  lower  end  of  the  brachial  artery,  /,  which  lies  under  the  superficial 
veins,  and  may  be  wounded  in  venesection,  has  been  laid  bare  by  reflecting 
a  piece,  C,  of  the  deep  fascia. 

In  this  situation  the  artery  is  very  near  the  surface  of  the  limb,  and 
is  covered  only  by  the  integuments  and  the  deep  fascia,  B.  Along  its 
outer  side  is  the  biceps  muscle,  A,  which  will  serve  as  the  guide  to  the 
vessel.     Underneath  it  lies  the  brachialis  anticus  muscle  (Plate  iv.,  F). 

One  large  accompanying  nerve,  median,  8,  is  placed  on  the  inner  side 
of  the  artery,  and  the  median  basilic  vein  crosses  over  it. 

Only  superficial  offsets  are  furnished  to  the  integuments  from  this  part 
of  j;he  vessel. 

Ligature  of  the  artery  at  the  elbow  may  be  necessary  in  consequence 
of  a  wound  with  a  lancet  in  venesection,  or  with  any  other  cutting  instru- 
ment. 

In  the  case  of  a  wound  from  accident  the  vessel  requires  to  be  secured 
by  one  thread  above  and  another  below  the  injury;  and  with  the  sur- 
rounding textures  infiltrated  with  blood,  the  surgeon  may  experience 
some  difficulty  in  finding  the  ends  of  the  vessel,  unless  he  has  studied  the 
connections,  and  practised  previously  the  operation  of  applying  a  ligature 
to  the  artery  in  the  dead  body. 

In  an  operation  here  for  aneurism  after  a  wound,  as  when  the  vessel  is 
punctured  in  venesection,  the  tumor  is  to  be  opened,  and  the  contents  of 
the  sac  being  removed,  the  arterial  trunk  is  to  be  tied  above  and  t)elow 
the  opening  in  it. 

*  Surgical  Observations  on  Injuries  of  the  Head  and  on  Miscellaneous  Subjects, 
by  John  Abernethy,  F.R.S.;  4th  Edit.,  p.  135:  London,  1825. 


BRACHIAL  AKTERY  AT  THE  ELBOW.  35 

Cutting  down  to  the  artery  in  front  of  the  elbow  is  an  easy  operation 
in  the  dead  body.  Taking-  the  inner  edge  of  the  biceps  muscle  as  the 
superficial  guide  to  the  position  of  the  vessel,  an  incision  two  or  three 
inches  in  length,  and  paralled  to  the  artery,  may  be  carried  along  the 
biceps,  so  as  to  divide  the  integuments;  and  should  the  median  basilic 
vein  come  into  view  at  this  stage,  it  may  be  drawn  inwards.  The  deep 
fascia  is  next  to  be  cut  to  the  same  extent,  and  the  wound  is  to  be  moved 
inwards  over  the  line  of  the  artery. 

Deep  in  the  wound  the  firm  white  median  nerve  appears  on  the  inner 
side  of  the  arter}^  but  gradually  inclining  away  from  it  in  front  of  the 
elbow-joint;  this  nerve  will  serve  as  the  deep  guide  to  the  position  of  the 
vessel,  though  the  operator  should  be  aware  that  it  may  be  placed  away 
from  the  artery,  lying  along  the  inner  intermuscular  septum  of  the  arm,* 
The  nerve  being  recognized,  the  artery  is  to  be  sought  between  it  and  the 
edge  of  the  biceps. 

Lastly,  the  sheath  of  the  vessel  having  been  opened,  and  the  vense 
comites.  separated  from  the  artery,  the  aneurism  needle  may  be  passed, 
and  the  ligature  may  be  tied  in  the  usual  way. 

Some  unusual  conditions  of  the  arteries  in  front  of  the  elbow  deserve 
consideration  with  reference  to  the  operation  of  blood-letting.  The 
occasional  presence  of  an  artery  in  the  fat  with  the  superficial  veins  has 
been  before  noticed,  p.  34.  The  number  of  large  arteries  too  beneath  the 
fascia  may  vary.  Commonly  there  is  only  one,  the  brachial;  but  there 
may  be  two,  which  consist  of  the  brachial  trunk  and  the  radial  or  ulnar; 
and  lastly,  three  may  be  occasionally  found,  resulting  from  division  of  the 
brachial  into  its  usual  arteries  rather  above  the  elbow-joint,  and  the  un- 
usual origin  of  the  interosseous  from  the  brachial  high  in  the  arm.  f  The 
possibility  of  so  many  arteries  being  present  in  one  spot  must  suggest 
caution  to  the  student  about  to  bleed,  and  to  the  surgeon  undertaking  the 
operation  of  placing  a  ligature  on  a  wounded  artery  in  front  of  the  elbow. 

There  is  another  unusual  state  of  the  brachial  artery  which  would  give 
rise  to  unlooked-for  haemorrhage  from  a  wound  in  the  lower  half  of  the 
arm.     For  instance,  the  artery  leaves  sometimes  the  edge  of  the  biceps, 

*  1  have  met  with  three  examples  of  this  condition  in  the  dissecting-room  of 
University  College.  In  another  body  the  nerve  M'as  deeper  than  the  artery,  and 
was  covered,  above  the  elbow,  by  fibres  of  the  brachialis  anticus. 

•j-  The  facts  here  referred  to  shortly,  are  stated  fully  in  the  Surgical  Anatomy 
of  the  Arteries  by  Professor  Quain,  p.  259. 


36 


ILLUSTRATIONS    OF    DISSECTIONS. 


and  courses,  with  or  without  the  median  nerve,  along  the  line  of  the  inner 
intermuscular  septum,  D.  At  the  elbow  it  returns  to  the  middle  of  the 
limb  through  the  origin  of  a  wide  pronator  teres  muscle,  or  round  a  pro- 
jecting bony  point  of  the  humerus  (Qnain).  In  such  a  deviation  in  the 
course  of  the  artery,  a  wound  near  the  elbow  on  the  inner  side  of  the  arm,  far 
removed  from  the  line  of  the  biceps  muscle,  might  open  this  large  trunk, 
and  give  origin  to  most  alarming,  if  not  dangerous  haemorrhage. 


NERVES  BEFORE  THE  BEND  OF  THE  ELBOW. 

The   anterior  cutaneous  nerves  of  the  forearm  cross  the  superficial 
veins  in  front  the  elbow  in  coursing  to  their  destination. 


1.  Large  internal  cutaneous  nerve. 

2.  Small  internal  cutaneous,  or  the 

nerve  of  Wrisberg. 

3.  External  cutaneous  nerve. 

4.  Anterior  part  of  the  large  inter- 

nal cutaneous. 


5.  Cutaneous  off  sets  to  the  arm  of  the 

internal  cutaneous. 

6.  Posterior  part  of  the  internal  cuta- 

neous. 
8.  Median  nerve. 


The  large  iuteriicd  cutcmeous  nerve,  1,  enters  the  fat  about  midway 
along  the  arm,  and  divides  into  two  parts  : — One,  4  (the  anterior  part), 
is  continued  along  the  front  of  the  forearm  to  the  Avrist;  the  other,  6 
(posterior  part),  ramifies  on  the  back  of  the  forearm  on  the  ulnar  side, 
reaching  to  the  lower  third.  The  j)rimary  branches  of  the  nerve  lie  gener- 
ally under  the  median  basilic  vein,  instead  of  over  it  as  in  this  dissection. 

Near  the  arm-pit  a  cutaneous  offset,  5,  leaves  the  trunk  to  sujiply  the 
integuments  over  the  biceps  muscle. 

Small  internal  cutaneous  nerve,  2,  or  the  nerve  of  Wrisberg.  The 
origin  of  the  nerve  is  seen  in  the  arm-pit  in  Plates  i.  and  ii.  It  pierces 
the  fascia  internal  to,  and  lower  down  than  the  large  cutaneous  nerve, 
1;  and  it  ends  in  the  integuments  over  the  back  of  the  elbow.  Offsets 
are  directed  backwards  to  the  fat  and  skin  of  the  lower  j^art  of  the  \)0^- 
terior  surface  of  the  arm;  and  one  or  two  communicate  with  the  large 
internal  cutaneous  nerve. 

In  this  body  the  nerve  was  large,  and  was  placed  rather  farther  for- 
wards than  usual. 

The  external  cutaneous  nerve,  3,  or  the  terminal  part  of  the  musculo- 
cutaneous (Plate  ii.,  11),  appears  at  the  bend  of  the  elbow  beneath  the 


PLATL  IV 


vl^^ 


SURFACE    MARKING    OF    THE    ARM.  37 

median  cephalic  vein,/,  and  its  distributed  along  the  radial  side  of  the 
forearm  as  far  as  the  ball  of  the  thumb. 

The  median  nerve,  8,  is  continued  to  the  fingers.  At  the  upper  part 
of  the  dissection  it  lies  inside  and  near  the  brachial  artery,  but  opposite 
the  bend  of  the  elbow  it  begins  to  incline  inwards  from  that  vessel.  In 
the  lower  as  in  the  upper  part  of  the  arm  the  nerve  serves  to  guide  the 
surgeon  to  the  situation  of  the  large  vessel  of  the  limb. 


DESCRIPTION  OF  PLATE  IV. 


The  relative  position  of  the  muscles,  vessels,  and  nerves  of  the  inner 
side  of  the  arm,  after  the  removal  of  the  integuments  and  the  deep  fascia, 
is  shown  in  this  Plate. 

The  'skin  may  be  reflected  in  two  flaps  to  the  sides,  by  an  incision 
along  the  centre  of  the  arm,  Avith  a  cross-cut  at  each  end.  In  the  fat  the 
suiDcrficial  nerves  and  vessels  are  to  be  found;  and  then  the  remains  of  the 
fat,  and  the  deep  fascia,  should  be  taken  away.  A  small  part  of  the 
fascia  has  been  left  near  the  elbow,  f dr  the  purpose  of  marking  its  position 
to  the  superficial  veins  and  the  lymphatic  glands. 

SURFACE  MARKING  OF  THE  ARM. 

Along  the  front  of  the  arm  is  the  well-marked  muscular  prominence  so 
evident  in  the  Plate.  Before  the  removal  of  the  integuments  and  fascia, 
this  eminence  seems  to  the  feel  to  be  formed  by  one  muscle;  but  after  the 
dissection  has  been  made,  it  will  be  seen  to  consist  of  the  bice^Ds,  D,  and 
coraco-brachialis,  H,  which  may  be  traced  upwards  under  the  anterior 
fold,  K,  of  the  arm-jjit.  As  the  chief  muscle,  D,  acts  as  a  flexor  of  the 
elbow-joint,  it  becomes  much  enlarged  in  persons  occupied,  like  black- 
smiths, in  bending  the  elbow. 

On  each  side  of  the  swell  of  the  muscles  is  a  surface  depression  :  the 
two  meet  below  in  a  hollow  in  front  of  the  elbow,  which  contains  the 
superficial  veins  and  nerves  ;  but  above  they  separate,  the  inner  one  join- 


38 


ILLirSTRATIONS    OF    DISSECTIONS. 


ing  the  arm-pit,  and  the  outer  one  subsiding  at  the  insertion  of  the  del' 
toid  muscle,  S. 

In  the  inner  depression,  which  is  most  marked,  lies  the  basilic  vein, 
(),  with  the  large  internal  cutaneous  nerve,  4,  and  lympathics  :  these  are 
contained  in  the  fat,  and  are  usually  distant  a  short  way  from  the  edge 
of  the  biceps.  Beneath  the  fascia  of  the  limb  and  close  to  the  muscle  are 
lodged  the  brachial  vessels,  1c,  and  the  companion  median  nerve,  7. 

The  outer  depression  is  less  wide  and  deep,  and  corresponding  with  it 
is  the  superficial  vein,  the  cephalic,  li.  In  it,  towards  the  elbow,  the  ex- 
ternal cutaneous  nerve  of  the  forearm  makes  its  appearance  though  the 
fascia  (Plate  iii.  3). 

Wounds  in  the  outer  bicipital  hollow  may  be  large  and  deep  without 
injuring  any  important  part ;  whilst  m  the  inner  one  scarcely  a  puncture 
can  be  made  without  endangering  some  vessel  or  nerve.  The  issue, 
seton,  and  cautery  are  applied  usually  at  the  top  of  the  outer  bicipital 
groove,  just  below  the  insertion  of  the  deltoid  muscle,  because  the  spot 
13  free  from  any  active  subjacent  muscle  to  give  rise  by  its  contractions 
to  pain  in  the  sore  that  has  been  produced. 


MUSCLES    AND   FASCIA    OF    THE    ARM. 


The  muscles  on  the  front  of  the  humerus  which  pass  over  the  elbow, 
viz.,  the  biceps,  D,  and  the  brachialis  anticus,  F,  bend  the  elbow-joint 
by  bringing  forwards  the  bones  of  the  forearm,  to  which  they  are  fixed. 
Behind  the  humerus  is  a  large  three-headed  or  tricipital  muscle  which  is 
attached  to  the  ulna,  and,  drawing  backwards  that  bone,  acts  as  an  anta- 


gonist to  the  flexor  muscles. 


A.  Fascia  of  the  forearm. 

B.  Offset  to  the  fascia  from  the  ten- 

don of  the  biceps. 

C.  Inner  intermuscular  septum  of 

the  arm. 

D.  Biceps  flexor  brachii  muscle. 
F.  Brachialis  anticus  muscle. 
H.  Coraco  brachialis  muscle. 


K.  Inner  head  of  the  triceps  extensor 

muscle. 
M.  Middle  head  of  the  triceps. 
N.  Teres  major  muscle. 
P.  Latissimus  dorsi  muscle. 
R.  Pectoralis  major  muscle. 
S.  Deltoid  muscle. 


The  deeji  fascia  of  the  arm  is  continuous  with  that  of  the  forearm.  A, 
and  is  attached  to  the  prominences  around  the  elbow.     C   marks  the 


MUSCLES   AND    FASCIA    OF   THE    ARM.  39 

inner  iiitermuscuhir  septum  of  tlic  arm,  wliicli  is  inserted  into  the  con- 
dyloid ridge  of  the  humerus,  and  gives  origin  in  front  to  the  bracliialis 
antieus,  F,  and  behind  to  the  inner  head  of  tlie  triceps,  K.  In  front  of 
the  septum  a  piece  of  the  fascia  has  been  left  with  superficial  lympliatic 
glands  on  it.  At  B,  an  offset  from  the  tendon  of  the  biceps  joins  the 
fascia. 

Biceps  hrachii  muscle,  D.  The  origin  by  two  heads  from  the  scapula, 
is  shown  in  Plate  ii.  Half  way  along  the  arm  the  heads  blend  in  a  fleshy 
belly  ;  and  the  muscle  is  inserted  below  by  a  tendon  into  the  tubercle  of 
the  radius,  after  giving  a  fibrous  process,  B,  to  the  deep  fascia.  A  third 
slip  or  head  arises  occasionally  from  the  middle  of  the.  humerus  ;  and  if  it 
crosses  over  the  main  vessels,  as  it  is  directed  outwards,  it  may  complicate 
the  operation  of  tying  the  artery. 

Except  at  the  origin  and  insertion  the  muscle  is  superficial ;  and  it 
covers  partly  the  other  two  muscles  in  front  of  the  humerus,  viz.,  the 
coraco-brachialis,  H,  and  brachialis  antieus,  F.  Along  the  inner  edge 
lie  the  brachial  artery,  h,  and  the  accompanying  veins  and  nerves ;  and 
along  the  outer  edge  is  the  cephalic  vein,  ]i. 

The  muscle  flexes  the  elbows-joint  by  acting  on  either  the  radius  or 
the  humerus,  according  as  the  one  or  the  other  may  be  free  to  be  moved. 
It  is  also  a  supinator  of  the  hand.  And  if  the  radius  is  fixed  it  can  assist 
in  carrying  the  limb  forwards  from  the  side.  As  the  muscle  contracts  in 
the  living  body  the  swell  of  its  belly  rises  towards  the  pectoralis  major. 

The  brachialis  antieus,  F,  arises  from  the  front  of  the  humerus  for 
the  lower  half  of  the  bone  ;  and  from  the  intermuscular  septum  on  each 
side,  viz.,  from  all  the  inner  one,  but  from  only  the  upper  part  of  the 
outer  one,  some  muscles  of  the  forearm  excluding  it  below  (Plate  xii,). 
It  is  inserted  into  the  fore  part  of  the  coronoid  process  of  the  ulna. 

Resting  on  the  humerus  and  the  elbow-joint,  it  is  concealed  by  the 
biceps,  and  vessels  and  nerves.  Sometimes  a  fleshy  slip  from  it  covers 
the  brachial  artery  or  the  median  nerve  at  the  lower  part  of  the  arm. 

This  muscle  reaches  over  the  elbow,  and  is  the  chief  agent  in  bending 
that  joint. 

The  coraco-lrachialis  muscle,  H,  is  shown  better  in  Plate  li.,  to  which 
reference  may  be  made. 

The  triceps  extensor  cubit i  consists  above  of  three  parts  or  heads  ;  and 
its  anatomy  will  be  given  more  fully  in  the  description  of  Plate  vi. 

The  middle  head,  M,  arises  from  the  scapula;  and  the  inner  and  outer 


40 


ILLUSTRATIONS    OF    DISSECTIONS. 


heads  are  attaclied  to  the  humerus  and  the  intermuscular  septa.  The 
insertion  of  the  muscle  into  the  olecranon  process  of  the  ulna  will  be 
afterwards  seen. 

In  this  view  of  the  parts  the  middle  head  lies  beneath  the  teres  major, 
N,  and  latissimus  dorsi,  P,  and  touches  the  brachial  vessels  and  their 
companion  nerves  for  one  to  two  inches.  And  the  inner  head  surrounds 
the  ulnar  nerve,  8,  and  the  inferior  profunda  artery,  n :  this  is  more  evi- 
dent in  Plate  vi. 

The  teres  major,  N,  and  latissimus  dorsi,  P,  coming  forwards  to  their 
insertion  into  the  humerus,  bound  behind  the  hollow  of  the  axilla  (Plate  i.). 

The  pectoralis  major,  E,  curves  over  the  muscles  of  the  front  of  the 
arm  as  it  passes  from  the  thorax  to  its  insertion  into  the  humerus.  At 
its  attachment  to  the  bone,  it  joins  the  deltoid  muscle,  S. 

VEINS    OF    THE    ARM. 


The  superficial  veins  of  the  limb  diminish  in  number  from  the  hand 
upwards.  At  the  elbow  they  blend  into  two,  which  have  a  constant 
course  on  the  sides  of  the  biceps  muscle  to  the  axilla.  A  somewhat  dif- 
ferent arrangement  from  that  in  Plate  iii.  is  here  noticeable. 


a.      Median  vein  of  the  forearm. 
6  6.  Anterior  ulnar  veins. 

c.  Posterior  ulnar  vein. 

d.  Median  cephalic  vein. 
/.       Median  basilic  vein. 


g.  Basilic  vein  of  the  arm. 
h.  Cephalic  vein  of  the  arm. 
s.  Inner  companion  vein  of  the  bra- 
chial artery. 


The  median  vein,  a,  splits  in  the  usual  way  into  two  branches,  Avhich 
are  directed  outwards  and  inwards  to  receive  the  radial  and  ulnar  veins. 
In  this  body  the  anterior  ulnar  veins,  b,  b,  are  large,  and  join  the  median 
basilic,  /,  at  separate  points,  after  being  united  by  a  cross  branch. 

The  basilic  vein,  g,  formed  by  the  union  of  the  median  basilic  and 
anterior  ulnar  veins  near  the  elbow,  ascends  in  the  fat  to  the  middle  of 
the  arm ;  then  piercing  the  deep  fascia,  it  is  directed  onwards  to  the 
axilla  by  the  side  of  the  brachial  artery,  and  becomes  the  axillary  vein  at 
the  lower  border  of  the  teres  major  muscle.  Soon  after  it  sinks  through 
the  fascia  it  communicates  usually  with  one  of  the  companion  veins,  s,  of 
the  brachial  artery. 

Cephalic  veins,  h. — Only  the  upper  part  of  this  vein  is  visible  as  it 


ARTERIES    OF    THE    ARM. 


41 


crosses  between  the  muscles  great  pectoral,  R,  and  deltoid,  S,  to  end  in 
the  axillary  vein.  Springing  below  from  the  junction  of  the  median 
cephalic,  d,  with  the  radial  vein,  it  ascends  in  tlie  fat  to  the  shoulder 
outside  the  biceps  muscle.  An  unusual  superficial  artery  accompanied 
it  is  this  dissection. 

Ven(B  comites. — The  companion  veins  of  the  brachial  artery,  two  in 
number,  lie  one  on  each  side  of  that  vessel,  and  join  at  intervals  by  cross 
branches  ;  the  inner  one  is  marked  s  in  the  Plate.  Receiving  small 
veins  which  accompany  the  branches  of  the  artery,  they  join  commonly 
into  one  at  the  lower  part  of  the  axilla ;  and  this  ends  in  the  axillary 
vein  near  the  lower  border  of  the  subscapularis  muscle  (Plate  ii.  k). 

ARTERIES    OF    THE    ARM, 

The  brachial  artery  and  the  end  of  the  axillary  trunk  may  be  studied 
in  this  dissection  with  their  connections  undisturbed.  The  ramifications 
or  ending  of  the  branches  must  be  learned  with  the  aid  of  the  other 
Plates. 


k.  Brachial  artery. 

*    Spot  best  suited  for  ligature  of 

the  vessel. 
I.  External  mammary  branch  of  the 

axillary  artery. 


m.  Muscular  offset  of   the   superior 

profunda  branch. 
n.  Inferior  profunda  branch. 
p.  Anastomotic  branch. 


The  dracMal  artery,  k,  extends  from  the  lower  border  of  the  teres 
major  muscle,  IST,  to  a  finger's  breadth  below  the  bend  of  the  elbow 
(Quain),  where  it  bifurcates  into  the  radial  and  ulnar  arteries.  The 
inner  edge  of  the  muscular  prominence  of  the  coraco-brachialis  and 
biceps  marks  its  position  in  the  limb  ;  or  a  line  from  the  arm-pit  to  the 
middle  of  the  bend  of  the  elbow  would  correspond  with  the  course  of 
the  vessel. 

In  consequence  of  its  superficial  position  in  the  arm  the  vessel  can  be 
readily  compressed.  Above  the  spot  marked  with  an  asterisk  the  artery 
lies  inside  the  humerus,  and  pressure  to  act  on  it  should  be  directed  out- 
wards against  the  bone  ;  but  below  that  spot  it  inclines  in  front  of  the 
bone,  and  the  blood  will  be  stopped  in  it  by  forcing  backwards  the  fin- 
ger or  the  thumb. 

Its  connection  with  muscles  and  fascia  are  the  following  : — Beneath 


42  ILLUSTRATIONS    OF   DISSECTIONS. 

it,  from  above  down,  are  the  long  head  of  the  triceps,  M;  the  inner  head, 
K,  of  the  same  muscle;  the  coraco-brachialis,  H,  where  the  asterisk  is 
placed,  and  thence  to  the  ending,  the  brachialis  anticus,  F.  Superfi- 
cial to  the  artery  is  the  deep  fascia  of  the  limb  with  the  integuments. 

Two  companion  veins  are  close  to  the  brachial  trunk — one  on  each 
side — and  anastomose  across  it  after  the  manner  of  such  veins;  and  at 
the  bend  of  the  elbow  the  median  basilic  vein,  /,  crosses  the  artery.  The 
basilic  vein,  g,  lies  inside  the  line  of  the  vessel — sometimes  nearer, 
and  at  others  farther  from  it. 

Several  nerves  accompany  the  artery  above,  but  only  one  below.  The 
median  nerve,  7,  keeps  close  to  the  vessel  throughout,  except  in  front  of 
the  elbow,  where  it  inclines  away  to  the  inner  side  ;  as  low  as  the  part 
marked  thus  *  it  is  outside  the  vessel,  then  it  crosses  gradually  over, 
though  occasionally  under  the  artery,  and  gains  the  inner  side  about  two 
inches  above  the  elbow.  The  ulnar  nerve,  8,  lies  inside  and  in  close  con- 
tact with  the  artery  nearly  to  the  asterisk,  but  at  that  spot  it .  diverges 
from  the  vessel  and  courses  along  the  inner  intermuscular  septum.  The 
musculo-spiral  nerve  is  placed  behind  the  upper  part  of  the  artery  for  two 
inches  (see  Plate  vi.).  The  large  internal  cutaneous  nerve,  4,  rests  on 
the  upper  third  of  the  brachial  artery  ;  but  in  some  bodies  it  is  moved 
farther  in,  as  in  the  dissection  from  which  the  drawing  was  taken. 

Position  and  names  of  the  hrayicJies.  Besides  small  muscular  and 
cutaneous  offsets,  four  named  branches  spring  from  the  brachial  trunk. 
The  highest  and  largest,  upjjer  profunda,  leaves  the  back  of  the  artery 
about  an  inch  from  the  beginning.  The  next  largest,  the  inferior  pj'O- 
funda,  n,  arises  near  the  upper  end  of  the  inner  intermuscular  septum. 
A  nutritive  artery  of  the  shaft  of  the  humerus  begins  near  the  last,  and 
is  covered  by  the  biceps.  Another  small  branch,  the  anastomotic  artery, 
p,  comes  from  the  parent  trunk  near  the  elbow. 

All  the  branches  are  small  except  the  superior  profunda  ;  and  no  two 
arise  at  opposite  sides  of  the  trunk  to  interfere  by  a  cross  current 
with  the  healing  process  after  a  thread  has  been  put  on  it.  Almost  any 
point  would  therefore  be  available  for  the  application  of  a  ligature;  but 
the  spot  generally  selected  is  marked  with  an  asterisk  in  the  Plate,  the 
vessel  being  here  free  from  any  large  offset,  and  being  firmly  supported  by 
the  coraco-brachialis  and  the  humerus. 

Ligature  at  the  7niddle  of  the  artery.  This  operation  on  the  brachial 
trunk,  without  a  wound  at  the  spot  where  it  is  tied,  is  sometimes  ren- 


LIGAlTURE    OF   THE    BRACHIAL.  43 

dercd  necessary  by  an  aneurism,  or  by  haemorrhage  from  a  vessel  lower 
in  the  limb. 

Under  ordinary  circumstances  the  operation  is  not  difficult,  as  the 
brachial  trunk  is  so  near  the  surface,  and  the  guides  to  the  vessel  are 
good.  Tlic  superficial  guide  to  the  position  of  the  artery  is  the  inner 
edge  of  the  bicej^s  muscle,  and  the  deep  guide  during  the  operation  is 
tlie  large  median  nerve. 

When  the  vessel  is  to  be  secured  the  operator  stands  on  the  inner  side 
of  the  limb,  and  fixing  his  eye  on  the  spot  thus  marked  *,  makes  a  cut 
two  or  three  inches  long  on  the  biceps  muscle  near  the  inner  edge,  but 
not  over  the  vessel.  The  skin,  fat,  and  deep  fascia  are  to  be  divided 
down  to  the  fleshy  fibres;  and  the  incision  is  then  to  be  moved  inwards 
over  the  line  of  the  brachial  artery,  the  loose  skin  readily  allowing  this 
shifting  of  its  position. 

Bending  now  the  elbow,  to  relax  the  biceps  muscle  and  allow  of  its 
being  kept  out  of  the  way,  the  firm  median  nerve  is  to  be  looked  for  close 
to  the  edge  of  the  biceps,  where  it  lies  outside  the  vessel,  or  is  coming 
inwards  over  the  arterial  trunk.  The  median  nerve  being  found,  and 
the  knife  having  been  carried  along  it  to  divide  its  sheath,  is  next  to  be 
drawn  inwards  from  the  edge  of  the  biceps  with  a  narrow  retractor,  but 
special  care  must  be  taken  not  to  draw  the  artery  out  of  place  with  the 
nerve.  Within  the  space  limited  by  the  nerve  on  the  one  side  and  the 
muscle  on  the  other,  the  operator  seeks  the  artery  by  cutting  away  the 
fat  bit  by  bit.  f 

Supposing  the  artery  recognized,  its  sheath  is  to  be  seized  with  the 
forceps,  and  a  piece  is  to  be  cut  out,  care  being  taken  that  the  point  of 
the  scapel  does  not  injure  the  vessel  beneath.  Without  loosing  the 
sheath  from  the  forceps  a  blunt  instrument,  like  the  point  of  a  director, 
may  be  inserted  into  the  hole  of  the  sheath  to  separate  the  artery;  and  on 
its  withdrawal  the  aneurism  needle  is  to  be  carried  round  the  vessel  in  the 
same  channel.  The  surgeon  avoids  detaching  the  artery  from  its  sheath 
more  than  is  required  for  the  passage  of  the  needle;  for  separation  of  the 


f  Some  experience  in  superintending  the  operations  of  students  on  the  dead 
body  has  convinced  me  of  the  expediency  of  directing  the  nerve  to  be  drawn 
inwards.  If  this  mode  of  proceeding  is  not  adopted,  the  beginner  comes  upon 
the  ulnar  nerve  and  the  basilic  vein,  which  he  may  mistake  for  the  median  nerve 
and  the  brachial  artery. 


44:  ILLDSTRATIONS   OF   DISSECTIONS. 

two  destroys  the  vasa  vasorum,  occasioning  the  death  of  the  arterial 
coats,  and,  as  a  consequence,  haemorrhage  may  follow  the  coming  away 
of  the  ligature. 

Let  the  ligature  be  put  on  the  vessel  as  high  as  the  sheath  is  detached; 
and  before  tying  it,  pressure  should  be  used  for  the  purpose  of  ascer- 
taining whether  the  circulation  through  the  chief  vessels  of  the  limb 
can  be  arrested.  Should  the  pulse  still  beat  as  before  at  the  wrist,  the 
existence  of  more  than  one  arterial  trunk  may  be  susjDected;  and  the 
operator,  after  tying  the  one,  seeks  another  by  its  side.  If  two  arteries 
are  present  both  are  to  be  secured;  for  the  object  in  view  when  putting 
a  ligature  on  the  brachial  trunk,  is  to  stop  the  entrance  of  the  blood  into 
the  limb  through  the  main  vessel,  and  to  insure  its  coming  in  only  slowly, 
and  through  the  anastomosing  channels. 

Before  an  attempt  is  made  to  place  a  ligature  on  the  brachial  trunk, 
the  difficulties  likely  to  arise  from  different  states  of  the  artery  or  of  the 
surrounding  parts  should  be  well  considered. 

An  unusual  position  of  the  brachial  artery  has  been  observed.  In  the 
condition  referred  to  the  vessel  separates  from  the  biceps  above,  or  about 
midway  between  the  arm-pit  and  elbow,  and  courses  through  the  arm 
along  the  inner  intermuscular  septum,  C  (p.  35).  So,  in  an  ojjeration 
at  the  usual  spot,  if  the  main  blood-vessel  cannot  be  found  by  the  side 
of  the  muscle,  it  should  be  sought  further  in,  or  nearer  the  inner  border 
of  the  limb.  * 

There  maybe  more  than  one  large  artery  in  the  limb  as  before  said. 
Two  vessels  have  been  found  as  frequently  as  1  in  5,  and  the  surgeon 
may  expect  therefore  to  meet  with  this  condition,  f  When  two  vessels 
are  present  they  usually  lie  side  by  side  in  the  place  of  the  brachial;  and 
their  existence  might  be  inferred  in  an  operation  in  consequence  of  the 
smaller  size  and  more  superficial  position  of  the  vessel  first  found.  But 
sometimes  the  two  are  not  in  contact  with  each  other:  thus,  one,  the 
smallest  (radial)  may  lie  in  the  place  of  the  brachial  trunk;  and  the 


*  Two  instances  of  this  kind  were  met  with  during  operations  on  the  dead 
body,  and  have  been  put  on  record  by  Mr.  Quain  :  "  Commentaries  on  the  Arte- 
ries," p.  259.  I  have  observed  a  similar  unusual  place  of  the  artery,  with  diffi- 
culty in  finding  the  vessel,  whilst  I  was  engaged  in  superintending  the  operations 
of  students. 

f  The  Anatomy  of  the  Arteries,  by  Mr.  Quain. 


BRANCHES    OP    THE    BRACHIAL.  45 

other,  the  larger  artery,  may  be  moved  inwards  from  tlie  edge  of  the 
biceps  to  the  inner  intermuscuhir  septum. 

The  depth  of  the  artery  varies  Avith  different  states  of  the  biceps  mus- 
cle. Sometimes  the  brachial  trunk  is  covered,  at  tlie  spot  where  ligature 
is  practised,  by  a  fleshy  slip  of  origin  of  the  biceps  from  the  humerus. 
The  presence  of  fleshy  fibres  over  the  artery  would  cause  some  embarrass- 
ment to  an  operator  unacquainted  with  that  fact;  and  the  knowledge  of 
the  occasional  existence  of  this  condition  teaches,  that  a  previous  exami- 
nation of  the  arm  should  be  m.ade,  with  the  view  of  detecting  it  by  the 
difference  in  the  force  of  the  pulsations  of  the  artery. 

Change  in  the  position  of  the  median  nerve  with  respect  to  the  brachial 
artery  may  bring  danger  in  an  operation,  as  the  nerve  serves  as  the  deep 
guide  to  the  vessel.  In  the  ordinary  arrangement  the  nerve  is  superficial 
to  the  artery,  and  is  met  with  first;  but  not  unfrequently  it  crosses  under 
the  artery,  and  would  not  be  found  so  soon  as  the  vessel.  When  this  last- 
named  position  of  the  nerve  exists,  the  danger  of  wounding  the  artery 
or  its  companion  veins  is  increased  in  consequence  of  these  being  nearer 
the  surface,  and  being  reached  unexpectedly. 

Brandies  of  the  artery. — The  offsets  of  the  artery  are  small  and  nume- 
rous, but  only  a  few  have  received  names.  After  supplying  the  muscles 
and  contiguous  parts  the  chief  branches  course  to  the  elbow,  and  join 
offsets  of  the  trunks  in  the  forearm. 

^\\Q,  superior  profunda  branch  arises  from  the  trunk  of  the  artery 
above  the  letter,  h,  and  Avinds  to  the  back  of  the  arm,  where  it  ramifies 
in  the  triceps,  and  ends  at  the  elbow.  (See  Plate  vii.)  One  offset  is 
marked,  m,  in  the  Drawing. 

The  inferior  profunda,  n,  arises  near  the  spot  Avhich  is  commonly 
chosen  for  ligature  of  the  trunk,  and  runs  along  the  ulnar  nerve  to  the 
elbow:  it  anastomoses  with  the  posterior  recurrent  branch  of  the  ulnar 
artery. 

The  nutritive  artery  of  the  shaft  of  tlie  humerus  arises  between  k,  and 
*,  and  entering  an  osseous  canal,  supplies  the  medullary  structure  of  the 
bone. 

The  anastomotic  branch,  p,  is  directed  inwards  through  the  inner 
intermuscular  septum,  and  communicates  with  the  inferior  profunda,  n. 
An  offset  descends  in  front  of  the  elbow  joint,  supplying  the  brachialis 
anticus  and  one  or  more  muscles  of  the  forearm,  and  anastomoses  Avith 
an  anterior  recurrent  branch  from  the  ulnar  artery. 


46 


ILLUSTRATIONS    OF    DISSECTIONS. 


Muscular  offsets  spring  from  the  trunk  at  intervals,  and  supply  the 
muscles  on  the  fore  part  and  the  back  of  the  humerus. 

Small  cutajieous  offsets  to  the  arm  are  shown  coming  from  the  end  of 
the  brachial,  and  the  end  of  the  axillary  artery. 

Anastomoses  of  the  branches. — After  ligature  of  the  brachial  artery 
the  blood  is  conveyed  into  the  limb  by  the  anastomosis  of  the  branches 
arising  above,  with  those  beyond  the  spot  tied.  Thus  the  superior  pro- 
funda joins  behind  the  elbow  with  the  anastomotic  and  the  recurrent 
interosseous;  and  on  the  outer  side  with  the  recurrent  branch  from  the 
radial  artery  (Plate  vii.).  The  inferior  profunda  communicates  with 
the  anastomotic,  and  with  the  posterior  recurrent  of  the  ulnar  (Plate 
viii.).  And  the  anastomotic  branch,  joining  the  profunda,  transmits 
its  blood  to  the  anterior  recurrent  branch  of  the  ulnar  (Plate  viii.). 
The  artery  entering  the  shaft  of  the  humerus  will  anastomose  above  and 
below  with  the  vessels  supplied  to  the  ends  of  the  bone. 

NERVES    OF    THE    ARM. 

All  the  nerves  included  in  this  dissection  are  derived  from  the  bra- 
chial plexus  in  the  axilla,  with  the  exception  of  the  small  offsets  over  the 
shoulder,  which  come  from  the  cervical  plexus  in  the  neck.  Only  a  part 
of  each  trunk  is  laid  bare,  as  it  passes  onwards  to  its  destination  in  the 
forearm. 


1 .  Internal  cutaneous  branch  of  the 

niusculo-spiral. 

2.  Branch  of  the  musculo-spiral  to 

the  inner  and  middle  heads  of 
the  triceps. 

3.  Nerve  of  Wrisberg  or  small  in- 

ternal cutaneous. 

4.  Internal  cutaneous  (large). 


5.  Anterior  branch   of   the   internal 

cutaneous. 

6.  Posterior  branch  of  the  internal 

cutaneous. 

7.  Median  nerve. 

8.  Ulnar  nerve. 

9.  Branches  of  the  cervical  plexus. 


The  trunk  of  the  musculo-spiral  nerve,  lying  beneath  the  brachial 
artery,  furnishes  a  cutaneous  branch,  1,  to  the  integuments  of  the  back 
of  the  arm;  this  reaches  as  far  as  the  lower  third,  or  sometimes  nearly  to 
the  elbow.  A  muscular  branch,  2,  to  the  inner  head,  K,  and  the  middle 
head,  M,  of  the  triceps,  arises  in  common  with  the  preceding. 

The  nerve  of  Wrisberg,  3,  and  the  large  internal  cutaneous,  4,  pierce 


LYMPHATICS    OF    THE    ARM.  47 

the  fascia  of  the  arm  rather  below  Lhe  middle,  and  are  distributed  to  the 
integuments  of  the  back  of  the  arm  and  forearm:  their  position  internal 
to  the  brachial  artery  may  be  noticed.  Usually  the  cutaneous  nerve,  4, 
lies  over  the  ujiper  part  of  the  artery.  Its  place  at  the  elbow  under  the 
median  basilic  vein  is  regular:  for  another  arrangement,  see  Plate  iii. 

The  median  nerve,  7,  takes  the  same  course  in  the  arm  as  the  brachial 
artery,  and  lies  close  to  that  vessel  (p.  46).  Outside  the  artery  above,  and 
inside  below,  it  crosses  over  the  bloodvessel  so  as  to  be  found  on  the  in- 
ner side  about  two  inches  above  the  elbow.  Sometimes  the  nerve  passes 
under  instead  of  over  the  artery  in  its  change  of  position  from  the  one 
side  to  the  other.     No  branch  is  distributed  from  it  in  the  upper  arm. 

Being  the  com23anion  nerve  to  the  main  artery,  it  changes  generally 
its  place  when  the  vessel  deviates  from  the  usual  site.  Thus  in  those  in- 
stances in  Avhich  the  brachial  artery  courses  along  the  inner  intermuscular 
septum  to  the  elbow  the  nerve  usually  accompanies  it;  but  the  nerve  may 
be  near  the  septum  without  the  bloodvessel  (p.  35).  In  this  last  case  a 
wound  just  above  the  elbow  might  cut  through  the  nerve,  and  interfere 
with  the  actions  of  the  parts  supplied  by  it;  or  from  the  close  contiguity 
of  the  ulnar  and  median  nerves,  one  being  before  and  the  other  behind 
the  intermuscular  septum,  C,  the  same  wound  dividing  both  trunks  would 
cause  loss  of  power  in  the  muscles  on  the  front  of  the  limb  below  the  elbow, 
with  insensibility  in  the  fin2:ers  and  the  palm  of  the  hand,  and  in  the 
part  in  the  back  of  the  hand. 

The  ulnar,  nerve  passes  through  the  upper  arm  without  branching, 
and  enters  the  forearm  behind  the  elbow-jomt.  As  far  as  the  middle  of 
the  arm  the  nerve  is  close  to,  and  rather  behind  the  brachial  artery;  but  it 
separates  afterwards  from  the  vessel,  passing  through  the  intermuscular 
septum,  and  is  continued  behind  this  piece  of  fascia  to  the  hollow 
between  the  olecranon  and  the  inner  condyle  of  the  humerus.  Pressure 
applied  to  it  behind  the  elbow-joint  causes  a  peculiar  tingling  along  the 
inner  side  of  the  hand,  and  in  the  inner  two  fingers. 

LYMPHATICS    OF    THE    ARM. 

Superficial  lymphatics  accompany  the  suiDerficial  veins  in  the  arm; 
and  the  greater  number  lie  along  the  inner  part  of  the  limb.  Above  the 
elbow  are  some  superficial  lymphatic  glands  in  front  of  the  intefmusclar 
septum,  which  are  marked  thus,  f  t  t  j  these  are  the  lowest  superficial 


48  ILLUSTRATIONS   OF   DISSECTIONS. 

glands  in  the  limb.  Three  glands  were  present  in  the  dissection.  En- 
largement of  those  glands  may  be  brought  on  by  causes  which  induce 
inflammation  and  swelling  of  lymphatic  glands  elsewhere;  and  a  small 
tumor  in  this  part  of  the  arm  may  be  owing  to  an  increase  of  one  of 
the  glands. 

Deep  lymphatics  with  their  appertaining  glands  course  with  the  trunks 
of  the  bloodvessels  beneath  the  fascia,  and  enter  the  glands  in  the  axilla. 


DESCRIPTIONS^  OF  PLATE  V. 


This  view  exhibites  the  dissection  of  the  shoulder,  and  that  of  the 
superficial  muscles  and  vessels  of  the  back  of  the  scapula. 

On  the  detached  limb  this  dissection  will  follow  the  examination  of 
the  subscapularis  muscle  on  the  under  surface  of  the  scapula;  and  it  is 
readily  made  by  reflecting  the  integuments  and  the  deej)  fascia  from  before 
backwards  towards  the  lower  angle  of  the  blade-bone.  By  cutting 
through  the  deltoid  near  its  upper  attachment,  the  vessels  and  nerve 
beneath  it  can  be  traced  out. 


MUSCLES    OF    THE    SCAPULA,    SHOULDEE,    AND    ARM. 

Three  groups  of  muscles  are  laid  bare  more  or  less  completely  in  the 
dissection,  viz.,  the  muscles  of  two  borders  of  the  scapula;  those  of  the 
posterior  surface  of  that  bone;  and  those  of  the  shoulder  and  the  back  of 
the  arm. 

All  the  muscles  passing  between  the  humerus  and  the  scapula  are 
relaxed,  and  are  consequently  wide  and  hanging;  but  in  Plate  vi.  the 
muscles  are  shown  on  the  stretch,  where  the  difference  in  their  form  and 
position  may  be  noted. 

The  dorsal  muscles  of  the  scapula  cover  the  shoulder- joint,  and  will 
receive  injury  in  dislocation  of  the  head  of  the  humerus. 


PLATE  V 


,/U.^^^^'^4 


MUSCLES    OF   THE    SCAPULA    AND    SHOULDER. 


49 


A.  Rhomboideus  major. 

B.  Rhomboideus  minor. 

C.  Levator  anguli  scapulae. 

D.  Teres  major. 

E.  Latissimus  dorsl. 

F.  Long  head  of  the  triceps. 

G.  Outer  head  of  the  triceps. 


H.  Supra-spinatus. 
K,  Infra-spinatus. 
L.  Teres  minor. 
N.  Deltoid  muscle. 
O.  Fascia    on    the    dorsal    scapular 
muscles. 


The  three  muscles  marked  A,  B,  C,  arise  from  the  spinal  column, 
and  are  fixed  into  the  base  of  the  scapula. 

The  rliomloideus  major,  A,  is  inserted  between  the  spine  and  the 
lower  angle  of  the  bone. 

The  1'liomhoideus  minor,  B,  is  attached  opposite  the  smooth  surface  at 
the  root  of  the  spine. 

The  levator  anguli  scapulm,  C,  is  fixed  above  the  last,  reaching  from 
it  to  the  upper  angle  of  the  shoulder-blade. 

From  the  direction  of  their  fibres  the  muscles,  when  acting  without 
the  trapezius,,  would  lower  the  pomt  of  the  shoulder,  by  raising  and 
bringing  towards  the  spinal  column  the  lower  angle  and  base  of  the 
scapula. 

Connected  with  the  inferior  border  of  the  scapula  are  the  teres  major 
and  the  long  head  of  the  triceps;  and  the  latissimus  dorsi  crosses  the 
others,  resting  on  the  inferior  angle  of  the  bone. 

The  teres  major,  D,  arises  from  a  sj)ecial  impression  on  the  lower 
angle  of  the  scapula,  from  the  deep  fascia  covering  the  dorsal  scapular 
muscles,  and  from  the  lower  edge  of  the  scapula  as  far  forwards  as  an 
inch  from  the  long  head  of  the  triceps.  It  bounds  the  axilla  behind,  and 
lies  in  front  of  the  long  head  of  the  triceps  (Plates  i.  and  ii.). 

The  muscle  diverges  in  front  from  the  axillary  border  of  the  scapula, 
leaving  a  triangular  interval  between  it  and  the  bone;  and  it  is  concealed 
partly  by  the  latissimus  dorsi,  E,  when  viewed  from  behind. 

The  latissimus  dorsi,  E,  is  attached  to  the  lower  part  of  the  trunk  of 
the  body  by  the  one  end,  and  to  the  humerus  by  the  other.  Winding 
over  the  lower  angle  of  the  scapula  and  the  teres  major,  it  ascends  in 
front  of  che  teres  to  its  insertion  into  the  bicipital  groove  (Plate  ii.). 

In  the  dissection  the  muscle  slipped  down  somewhat  in  consequence 
of  its  relaxed  condition,  but  its  natural  place  on  the  angle  of  the  scapula 
is  displayed  in  Plate  vi. 

These  two  muscles  could  draw  the  arm  to  the  scapula  if  the  member 


50  ILLU8TEATI0NS    OF   DISSECTIONS. 

was  at  a  distance  from  the  trunk;  or  if  the  limb  was  fixed,  as  in  climb- 
ing, they  would  help  to  approximate  the  trunk  to  the  raised  limb. 

And  when  the  latissimus  has  drawn  the  humerus  backwards,  it  will 
rotate  inwards  that  bone.  If  the  lower  end  of  the  raised  humerus  is  not 
free  to  moye,  this  muscle  acting  with  the  teres  and  pectoralis  major 
draws  down  the  upper  end,  and  may  dislodge  the  head  from  the  articular 
surface  of  the  scapula. 

The  dorsal  scapular  muscles,  H,  K,  and  L,  cover  the  shoulder-joint 
above  and  behind,  and  converge  to  the  head  of  the  humerus.  A  deep 
fascia  covers  the  muscles,  and  gives  origin  to  the  fleshy  fibres  :  one  piece 
dips  between  the  two  infra-spinous  muscles,  K  and  L,  and  is  fixed  to  the 
scapula. 

The  swpra-spXnatus  muscle,  H,  fills  the  hollow  above  the  spine  of  the 
scapula.  Arising  from  the  bone  and  the  fascia,  it  passes  over  the  shoul- 
der-joint to  be  inserted  into  the  upper  impression  on  the  great  tuberosity 
of  the  humerus. 

The  infraspinatus  muscle,  K,  is  named  from  its  position  below  the 
spine  of  the  scapula.  It  arises,  like  the  preceding,  from  the  underlying 
bone  and  the  fascia  stretched  over  it;  and,  crossing  the  shoulder-joint,  it 
is  inserted  into  the  middle  impression  on  the  great  tuberosity  of  the 
humerus. 

The  superficial  fibres  from  the  spine  of  the  scapula  and  the  fascia 
arc  directed  forwards  over  the  fibres  coming  from  the  blade  part  of  the 
bone. 

The  teres  minor,  L,  arises  by  the  side  of  the  infra-spinatus  from  the 
fascia,  and  from  a  special  impression  along  the  axillary  border  of  the 
scapula.  Covering  the  joint,  it  is  inserted  into  the  lowest  mark  on  the 
gTcat  tuberosity  of  the  head  of  the  humerus,  and  into  the  bone  below  by 
a  few  fleshy  fibres. 

Tho  three  muscles  above  noticed  are  called  "articular"  from  touching 
the  joint.  When  in  action  they  cause  the  humerus  to  move  in  the  follow- 
ing directions.  If  the  bone  is  hanging  the  supra-spinatus  Avill  assist  the 
deltoid  in  raising  the  arm  ;  and  the  infra-spinatus  and  teres  minor  act- 
ing together  will  draw  backwards  the  point  of  the  bone  to  which  they  are 
fixed,  becoming  external  rotators.  If  the  humerus  is  elevated  the  two 
last  muscles  below  the  scapular  spine  will  assist  the  deltoid  in  carrying 
backwards  the  arm  almost  horizontally. 

They  suffer  more  or  less  injury  in  dislocations  of  the  shoulder- joint. 


MUSCLES    OF    THE    SCAPULA    AND    SHOULDER.  51 

Should  the  humerus  be  dragged  downwards  from  its  socket  all  three  may 
be  torn  across  ;  or,  the  muscles  remaining  whole,  a  shell  of  bone,  into 
which  they  are  inserted,  may  be  detached  from  the  humerus.  In  dis- 
I  location  backwards  the  head  of  the  humerus  lies  under  the  infra-spinatus, 
K,  and  teres  minor,  L,  Avhich  are  relaxed ;  and  the  supra-spinatus  is 
directed  backwards,  and  made  tense  round  the  spine  of  the  scapula.  But 
supposing  the  bone  dislocated  forwards  (on  to  the  other  side  of  the  scapula), 
the  infra-spinal  muscles  will  be  much  stretched  if  not  torn. 

The  two  arm  muscles  are  the  deltoid,  forming  the  prominence  of  the 
shoulder,  and  the  triceps,  which  lies  behind  the  arm  bone. 

The  deltoid  muscle,  N,  arises  from  the  scapular  arch  opposite  the  at- 
tachment of  the  trapezius,  viz.,  from  the  outer  third  of  the  clavicle,  and 
from  the  acromion  and  the  lower  edge  of  the  spine  of  the  scapula  as  far 
back  as  the  posterior  smooth  triangular  surface,  where  it  blends  with  the 
deep  fascia  covering  the  infra-spinous  muscles.  It  narrows  below,  and 
is  inserted  into  an  impression  on  the  outside  of  the  humerus  above  the 
middle.  Sufficient  of  the  muscle  has  been  divided  to  show  beneath  it  the 
head  of  the  humerus,  the  insertion  of  the  dorsal  scapular  muscles,  and 
the  posterior  circumflex  artery,  a,  and  nerve,  1. 

Between  the  acromion  process  and  the  deltoid  muscle,  on  the  one  side, 
and  the  head  of  the  humerus  with  the  dorsal  scapular  muscles  on  the 
other,  is  a  bursa — one  of  the  largest  in  the  body — which  lubricates  those 
surfaces  in  the  movements  of  the  arm.  In  chronic  rheumatic  arthritis, 
when  the  surrounding  capsule  and  muscles  are  destroyed,  this  bursa  com- 
municates with  the  articulation — the  deltoid  and  acromion  becoming 
incasing  structures  of  the  shoulder-joint. 

When  taking  its  fixed  point  above,  this  muscle  is  the  chief  elevator 
of  the  humerus,  and  it  can  carry  backwards  and  forwards  the  raised  limb; 
but  in  all  these  movements  it  is  assisted  by  the  scapular  muscles.  The 
arm  is  raised  by  the  central  fibres  of  the  deltoid  and  the  supra-spinatus 
muscle,  H;  it  is  moved  forwards  by  the  clavicular  fibres  and  the  subscap- 
ular is  ;  and  it  is  carried  back  by  the  fibres  attached  to  the  spine  of  the 
scapula,  and  by  the  infra-spinatus,  K,  and  teres  minor,  L. 

Supposing  the  deltoid  to  act  from  the  humerus,  as  in  drawing  along 
the  body  by  the  arms,  the  muscle  serves  as  the  chief  bond  of  union 
between  the  shoulder  and  arm  bones. 

Triceps  extensor  cuMti. — Two  heads  of  this  muscle,  outer  and  mid- 
dle, are  visible  in  the  Plate. 


52  ILLUSTRATIONS    OF    DISSECTIONS. 

The  outer  head,  G,  attached  to  the  upper  part  of  the  back  of  the 
humerus,  reaches  nearly  as  high  as  the  insertion  of  the  teres  minor,  L,  and 
is  covered  by  the  deltoid. 

The  middle  or  long  head,  F,  is  fixed  to  the-  inferior  costa  of  the  scap- 
ula close  to  the  shoulder-joint.  This  part  enters  between  the  two  teres 
muscles  (over  the  major  and  under  the  minor),  and  divides  into  two  the 
triangular  space  included  by  them.  In  front  of  the  head,  between  it  and 
the  humerus,  is  a  quadrangular  interval,  through  which  the  posterior 
circumflex  vessels  and  nerve  turn  from  the  axilla ;  and  behind  the  head 
is  an  opening  triangular  in  shape,  which  transmits  the  dorsal  branch  of 
the  subscapular  vessels. 

A  knowledge  of  the  attachments  of  the  muscles  to  the  upper  part  of 
the  humerus  will  be  serviceable  in  counteracting  in  fracture  of  that  bone 
the  displacement  of  the  fragments.  In  fracture  of  the  neck  of  the  bone 
near  the  teres  minor  insertion  the  upper  end,  into  which  the  three 
dorsal  scapular  muscles  are  inserted,  will  be  fixed  in  the  glenoid  hollow, 
and  tilted  rather  outwards.  Whilst  the  lower  end  will  be  inclined  in- 
wards towards  the  trunk  by  the  latissimus  dorsi,  teres  major,  and  pecto- 
ralis  major,  pulling  in  the  direction  of  their  fibres;  and  it  will  be  finally 
carried  upwards  inside  the  upper  fragment  by  the  contraction  of  the  mus- 
cles coming  from  the  scapula  to  the  humerus,  viz.,  deltoid,  coraco-bra- 
chialis,  and  triceps. 

In  an  oblique  fracture  lower  down  (about  opposite  N  on  the  deltoid) 
the  relative  position  of  the  fragments  to  each  other  would  be  reversed. 
In  that  case  the  upper  fragment  will  be  drawn  inwards  towards  the  trunk 
by  the  latissimus,  teres  major,  and  pectoralis  major ;  but  though  the 
lower  end  of  the  humerus  will  be  elevated  by  the  muscles  descending  from 
the  scapula,  as  before  said,  it  will  be  placed  outside  the  upper  end  by  the 
power  of  the  deltoid  muscle  alone. 


ARTERIES  OF  THE  SHOULDER. 

The  shoulder  possesses  few  vessels  in  comparison  with  some  other 
parts.  Two  small  arteries  with  their  veins  are  met  with  in  this  region, 
and  they  are  derived  from  the  axillary  trunk. 

The  posterior  circumflex  artery,  a,  one  of  the  lowest  branches  of  the 
axillary  trunk  (Plate  i.  h),  appears  between  the  humerus  and  the  long 


NEKVE    OF    THE    SHOULDER.  53 

licad  of  the  triceps;  and  winding  forwards  round  the  shaft  of  tlie  Imme- 
rus,  it  is  distributed  to  the  under  surface  of  the  deltoid  muscle. 

It  supplies  chiefly  the  deltoid,  but  offsets  enter  also  the  teres  minor, 
and  the  long  head  of  the  triceps.  Some  branches  arc  given  to  the  head 
of  the  humerus,  and  anastomose  in  front  with  the  anterior  circumflex. 
A  cutaneous  offset  descends  to  the  integuments  over  the  deltoid. 

In  the  operation  of  amputation  at  the  shoulder-joint  the  assistant  fol- 
lows the  knife  with  his  hands  to  seize  the  large  axillary  artery  when  it  is 
divided,  but  he  cannot  compress  at  the  same  time  the  circumflex  artery 
placed  much  farther  back.  This  vessel  pours  out  blood  freely,  and  it 
may  be  secured  first,  provided  the  assistant  controls  the  bleeding  of  the 
axillary  trunk. 

The  dorsal  scapular  artery,  h,  is  an  offset  of  the  subscapular  branch 
of  the  axillary  (Plate  ii.  /).  Appearing  through  the  triangular  space  be- 
hind the  long  head  of  the  triceps,  it  bends  round  the  edge  of  the  scapula 
under  the  teres  minor,  and  ramifies  in  the  infra-spinal  fossa. 

As  it  is  about  to  enter  the  fossa  a  branch  is  directed  along  the  inferior 
border  of  the  scapula,  between  the  teres  muscles,  to  which  and  the  integ- 
uments it  is  distributed. 


NERVE    OF  THE  SHOULDER. 

A  large  nerve  from  the  brachial  plexus  ramifies  under  the  deltoid 
muscle. 

The  circumflex  nerve,  1,  which  is  delineated  in  Plate  i.  12,  accom- 
panies the  posterior  circumflex  artery  to  the  shoulder.  Like  the  vessel 
it  ends  mostly  in  the  deltoid  muscle,  supplying  offsets  to  the  fleshy  fibres 
as  it  winds  over  the  humerus. 

Close  to  the  border  of  the  teres  minor  a  considerable  branch,  3,  breaks 
up  into  offsets  to  the  teres,  the  back  of  the  deltoid,  and  the  integuments 
covering  the  lower  part  of  the  deltoid  muscle.  In  the  natural  position  of 
the  integuments  the  cutaneous  branch  would  wind  forwards  over  the 
muscle. 

On  the  branch  to  the  teres  minor,  3,  there  is  usually  an  enlargement 
of  a  reddish  color  and  elongated  form,  which  has  been  designated  a 
"gangliform  swelling."  Before  the  nerve  is  disturbed  that  swelling  lies 
close  to  the  teres  muscle. 

In  consequence  of  the  loop  made  ,by  the  circumflex  nerve  under  the 


54 


ILLUSTRATIONS    OF    DISSECTIONS. 


head  of  the  humerus,  compression  of  it  -vvith  impairment  of  function  fol- 
lows dislocation  downwards  of  that  bone.  Paralysis  of  the  deltoid  muscle, 
with  inability  to  raise  the  arm,  will  follow  considerable  disease  or  injury 
of  the  circumflex  nerve. 


DESCRIPTIOX  OF   PLATE  VI. 


The  triceps  muscle  at  the  back  of  the  arm  and  some  of  the  snoulder 
muscles  are  here  displayed.  Whilst  the  Drawing  was  in  progress  the 
body  was  raised  on  blocks,  and  the  arm  was  fastened  over  the  side  of  the 
table. 

To  lay  bare  the  triceps  carry  an  incision  along  the  back  of  the  arm, 
and  reflect  the  integuments  and  the  deep  fascia  beyond  the  elbow.  Gen- 
erally the  limb  has  been  separated  from  the  trunk  before  the  student 
undertakes  the  dissection  ;  in  such  case  the  triceps  muscle  may  be  made 
tense  by  a  block  beneath  the  elbow. 


MUSCLES  OF  THE  ARM  AND  SHOULDER. 

On  the  back  of  the  humerus  lies  the  large  triceps  muscle,  which  ex- 
tends the  elbow-joint. 

The  shoulder  muscles  have  been  described  with  Plate  v.,  and  will  re- 
quire but  little  additional  notice;  the  scapular  muscles  are  more  stretched 
in  this  than  in  the  preceding  Plate. 


A.  Rhomboideus  major. 

B.  Latissimus  dorsi. 

C.  Teres  major. 

D.  Teres  minor. 

E.  Infra-spinatus. 

F.  Deltoid  muscle. 

G.  Inner  head  of  the  triceps. 


H.  Middle  head  of  the  triceps. 

K.  Outer  head  of  the  triceps. 

L.  Tendon  of  the  triceps. 

N.  Fascia  over  the  infra-spinatus. 

0.  Fascia  of  the  arm. 

P.  Spine  of  the  scapula. 


The  triceps  extensor  cuhiti  is  undivided  below,  but  is  split  into  three 
processes  of  origin  above,  viz.,  the  outer,  inner,  and  middle  heads. 


PLATE  V 


""%,•  "'''''*^ 
^"^ .  r^^ 


■■SKsast*"'' 


MUSCLES  '  OF    THE    ARM    AND    SHOULDER.  55 

The  outer  liead,  K,  is  attached  along  the  upper  lialf  of  the  posterior 
surface  of  the  humerus,  above  the  groove  for  the  musculo-spiral  nerve 
and  its  vessels,  and  reaches  upwards  nearly  to  the  teres  minor  (Theile).* 
This  attachment  is  represented  in  Plate  vii. 

The  inner  head,  G,  larger  below  than  above,  and  concealed  by  the 
middle  head,  arises  from  the  hinder  surface  of  the  humerus  below  the 
winding  groove,  extending  laterally  to  the  intermuscular  septa,  and  up- 
wards to  the  insertion  of  the  teres  major  (Theile).  See  Plate  vii.  for  its 
extensive  origin. 

The  middle  or  long  head,  H,  reaches  the  inferior  or  axillary  border  of 
the  scapula,  from  which  it  takes  origin  for  about  an  inch. 

The  outer  and  middle  heads  blend  about  the  middle  of  the  arm,  but 
the  inner  one  joins  lower  down.  The  muscle  ends  below  in  a  wide, 
strong  tendon,  which  receives  deep  jfleshy  fibres  down  to  the  elbow-joint, 
and  is  inserted  into  the  end  of  the  olecranon  process  of  the  ulna — a  small 
bursa  lying  between  the  tendon  and  the  tip  of  that  piece  of  bone. 

This  muscle  is  represented  in  the  thigh  by  the  extensor  muscle  of  the 
knee-joint.  It  is  subcutaneous  except  above;  and  it  is  separated  laterally 
from  the  muscles  in  front  of  the  humerus  by  processes  of  fascia — the 
intermuscular  septa.     The  long  head  lies  between  the  teres  muscles. 

By  the  action  of  this  muscle  the  elbow-joint  will  be  extended ;  and 
supposing  the  limb  removed  from  the  body,  it  can  be  approximated  to 
the  trunk  by  the  long  head.  But  should  the  upper  limb  be  fixed  at  a 
distance  from  the  side,  the  muscle  can  assist  in  moving  the  trunk  (through 
the  scapula)  towards  the  fixed  arm,  as  in  dragging  the  body  forwards  by 
a  rope. 

When  the  olecranon  process  of  the  ulna  is  detached  by  fracture,  it  is 
drawn  upwards  by  the  triceps,  as  far  as  the  lower  fleshy  fibres  of  the 
muscle  will  allow,  in  the  same  manner  as  the  upper  fragment  of  the 
patella,  in  transverse  fracture  of  that  bone,  is  carried  upwards  by  the  ex- 
tensor cruris.  When  replacing  the  displaced  fragment  force  is  not  to  be 
employed  alone  for  the  purpose  of  drawing  it  down  towards  the  end  of 
the  ulna  ;  but  the  interval  is  also  to  be  diminished  by  moving  backwards 
the  shaft  of  the  ulna  by  the  extension  of  the  elbow-joint. 

In  dislocation  forwards  of  the  humerus  the  olecranon  becomes  very 
prominent  behind  the  elbow,  and  the  tendon  of  the  extensor  muscle  stands 

*  See  a  foot-note  to  the  description  of  the  triceps  belonging  to  Plate  VII. 


56 


ILLUSTRATIONS    OF    DISSECTIONS. 


out  from  that  bone  something  like  the  tendo  Achilhs  in  the  leg.  Also 
some  of  the  lower  fleshy  fibres  will  be  broken  through  by  the  humerus 
being  forced  from  the  tendon. 

By  the  action  of  the  triceps,  fracture  of  the  lower  end  of  the  humerus 
near  the  elbow  may  be  made  to  resemble  the  dislocation  above  noticed; 
for  the  lower  end  of  the  bone  entering  into  the  elbow-joint  is  forced  up- 
wards behind  the  rest  of  the  shaft  by  the  contracting  muscle,  and  the 
olecranon  is  rendered  more  than  usually  prominent.  But  the  nature  of 
the  injury  may  be  made  out  by  attention  to  the  place  of  the  olecranon: — 
in  a  dislocation  this  point  of  the  bone  projects  much  beyond,  and  is 
higher  than  the  condyles  of  the  humerus,  but  in  fracture  of  the  bone  it  is 
not  more  prominent  with  respect  to  the  condyles  than  in  the  other  limb, 
and  it  retains  its  usual  position  on  a  level  with  them. 

Deltoid  muscle,  F. — At  the  origin  of  this  muscle  from  the  spine  of 
the  scapula  it  is  tendinous  behind,  and  blends  with  the  fascia  covering 
the  infra-spinatc  muscle.  The  hinder  part  of  the  muscle  has  been  turned 
forwards  to  allow  a  sight  of  the  circumflex  vessels  and  nerve  beneath 

Latissvnus  doi'si,  B. — The  muscle  has  been  cut  and  thrown  down  as  it 
crosses  the  angle  of  the  scapula;  the  extent  to  which  it  covers  that  point 
of  bone,  and  the  rhomboideus  major  and  teres  major  muscles,  may  be 
observed. 


ARTERIES  OF  THE  ARM  AND  SHOULDER. 

Tlie  trunk  of  the  brachial  artery  and  some  of  its  offsets  are  met  with 
in  the  dissection  of  the  back  of  the  arm.  Branches  of  the  axillary  artery 
are  distributed  to  the  shoulder. 


a.  Dorsal  scapular  artery. 
6.  Circumflex  artery. 
c.  Muscular  offset  of  the  superior 
profunda  artery. 


d.  Muscular  branch  of  the  brachial. 

e.  Trunk  of  the  brachial. 

/.  Muscular  branch  of  the  brachial. 
g.  Inferior  profunda  artery. 


The  hracMal  artery,  e,  is  visible  from  behind  where  it  lies  inside  the 
humerus,  but  it  disappears  below  by  passing  in  front  of  the  arm  bone. 
Contiguous  to  the  upper  part  of  the  artery  is  the  triceps  muscle,  viz.,  the 
middle  head,  H,  and  the  inner  head,  G.  A  large  companion  vein  (the 
continuation  of  the  basilic)  is  placed  on  the  inner  side. 


NERVES  OF  THE  SHOULDER  AND  ARM.  57 

Close  inside  the  artery  is  the  ulnar  nerve,  3;  and  intervening  between 
it  and  the  middle  head  of  the  triceps  is  the  musculo-spiral  nerve,  4. 

Two  muscular  offsets,  d,  and/,  enter  the  long  head  of  the  triceps. 

The  upper  profunda,  or  the  muscular  artery  of  the  back  of  the  arm, 
is  concealed  by  the  middle  head  of  the  triceps;  an  offset,  c,  from  it  enters 
the  outer  head  of  that  muscle.  The  distribution  of  this  branch  is  repre- 
sented in  Plate  vii. 

Inferior  profunda  artery,  g. — Winding  backwards  from  the  brachial 
(Plate  iv.),  it  accompanies  the  ulnar  nerve,  3,  to  the  interval  between  the 
olecranon  and  the  inner  condyle,  where  it  joins  a  branch  of  the  ulnar 
artery. 

The  dorsal  scapular  artery,  a,  courses  under  the  teres  minor  muscle, 
p.  53.  Amongst  the  surrounding  muscles  supplied  by  it  is  the  deltoid, 
to  which  it  gives  an  offset:  this  was  cut  through  in  the  dissection. 

The  position  of  the  poste7'ior  circumflex  artery,  I,  to  the  deltoid  ap- 
pears in  this  view  of  the  parts.  Some  of  its  muscular  offsets,  and  the 
branch  to  the  integuments,  are  apparent. 


NERVES  OF  THE  SHOULDER  AND  ARM. 

The  nerves  of  the  shoulder  and  back  of  the  arm  are  branches  of  the 
brachial  plexus,  and  have  been  partly  represented  in  other  Illustrations. 


1.  Ch-cumflex  nerve. 

2.  Offset  of  the  musculo-spiral  to  the 

middle  head  of  the  triceps. 


3.  Uluar  nerve. 

4.  Musculo-spiral  nerve. 


Circumflex  nerve,  1. — The  anatomy  of  the  trunk  of  the  nerve  can  be 
studied  in  Plate  v.  Its  cutaneous  offset  retains  its  natural  place  in  this 
dissection. 

The  musculo-spiral  nerve,  4,  winds  from  the  inner  to  the  outer  side 
of  the  limb  between  the  humerus  and  the  triceps  muscle  (Plate  vii. ).  The 
figure,  2,  marks  an  offset  from  it  to  the  middle  head  of  the  triceps. 

The  ulnar  nerve,  3,  lies  along  the  inner  side  of  the  arm  as  far  as  the 
elbow  (Plate  iv.).  In  the  lower  half  of  its  course  it  is  placed  at  the  back 
of  the  limb,  behind  the  inner  intermuscular  septum,  and  is  partly  con- 
cealed by  fibres  of  the  inner  head  of  the  triceps. 

In  excision  of  the  articular  ends  of  the  bones  of  the  elbow-joint 


58 


ILLUSTRATIONS    OF    DISSECTIONS. 


through  the  triceps,  the  ulnar  nerve  is  liable  to  be  cut.  To  secure  it 
from  accident  the  nerve  is  dislodged  from  its  hollow  during  the  operation, 
and  is  moved  to  the  front  of  the  projecting  inner  condyle  of  the  humerus. 
Temporary  loss  of  the  power  of  contraction  in  the  muscles,  and  of  feeling 
in  the  integuments  of  the  inner  part  of  the  forearm  and  hand,  follows 
division  of  the  nerve  ;  and  tliis  lost  power  would  not  be  regained  till  the 
nerve  structure  has  been  repaired. 


DESCRIPTION  OF  PLATE  VII. 


DissECTioisr  of  the  musculo-spiral  nerve  at  the  back  of  the  arm,  with 
its  accompanying  artery — the  jorofunda. 

Supposing  the  triceps  denuded,  as  in  Plate  vi.,  the  middle  and  outer 
heads  are  to  be  cut  through  after  the  manner  shown  in  the  Figure,  to 
trace  the  nerve  and  its  vessels.  At  the  outer  part  of  the  muscle,  a  small 
branch  of  nerve  and  artery  should  be  followed  through  the  fleshy  fibres  to 
the  anconeus  muscle  of  the  forearm. 


MUSCLES  OF  THE  ARM  AND  SHOULDER. 


After  the  triceps  has  been  divided  in  the  way  indicated,  the  attach- 
ment of  the  inner  and  outer  heajis  to  the  humerus  becomes  evident. 

The  shoulder  muscles  have  been  displaced  but  little  during  the  dissec- 
tion, but  they  are  shown  on  the  stretch  in  consequence  of  the  limb  being 
placed  in  a  hanging  posture. 


A.  Lower  end  of  the  long  head  of 

the  triceps  cut  through. 

B.  Upper  end  of  the  long  head  of 

the  triceps. 

C.  Outer  head  of  the  triceps. 
D.  F.  Inner  head  of  the  triceps. 

E.  The  nerve  and  vessels  to  the 

anconeus. 
G.  Anconeus  inuscle. 


H.  Supinator  longus  muscle. 

K.  Teres  minor  muscle . 

L.  Infra-spinatus  muscle. 

M.  Latissimus  dorsi  muscle. 

N.  Teres  major  muscle. 

P.  Deltoid  muscle. 

Q.  Outer  condyle  of  the  humerus. 

R.  Olecranon  process. 

S.  Fascia  of  the  forearm  reflected. 


PLATE  VI 


i-^^^m^  K 


\      > 


r,Sl      "^^ 


^ 

*■ 

If 

% 

^: 

a   M^ 


MUSCLES    OF    THE    ARM    AND    SHOULDER.  59 

Triceps  extensor  hrachii. — The  superficial  view  of  this  muscle,  and 
the  attachment  of  the  middle  head  can  be  seen  in  Plate  vi.  Only  the 
origin  bf  the  outer  and  inner  heads  will  be  noticed  below. 

The  outer  head,  0,  arises  at  the  back  of  the  humerus  above  the  groove 
in  the  bone,  which  lodges  the  musculo-spiral  nerve  and  the  vessels ;  it 
narrows  above  as  it  ends  near  the  insertion  of  the  teres  minor. 

The  inner  head,  D,  and  F,  arises  from  the  back  of  the  humerus  below 
the  winding  groove,  reaching  upwards  by  a  pointed  part  as  high  as  the 
teres  major  muscle — sometimes  to  the  upper,  and  sometimes  the  lower 
border.  This  head  is  wide  below,  and  reaches  laterally  to  the  inter- 
muscular septa,  from  which  fibres  take  origin.* 

Sula7ico7ieus. — Some  of  the  deepest  fibres  of  the  triceps  near  the  elbow 
terminate  in  the  capsule  of  the  joint,  like  fibres  of  the  extensor  of  the 
knee,  and  are  said  to  constitute  a  separate  muscle,  to  which  the  name 
subanconeus  has  been  applied  ;  but  I  have  not  observed  such  isolated  and 
distinct  muscular  bands  as  Anatomists  describe. 

Supinator  longus  muscle,  H. — Covered  by  the  fascia  of  the  limb  the 
muscle  is  fixed  to  the  outer  condyloid  ridge  of  the  humerus,  as  high  as 
the  groove  before  referred  to.  This  muscle  and  the  extensor  carpi 
radialis  longus  occupy  the  ridge — the  former  reaching  the  upper  two 
thirds,  and  the  latter,  the  lower  third.  Above  the  upper  border  of  the 
supinator  the  musculo-spiral  nerve  and  vessels  are  directed  forwards. 

The  group  of  shoulder  muscles  is  strained  by  the  weight  of  the  arm, 
as  in  Plate  vi. 

Naturally  the  teres  7ninor  muscle,  K,  is  not  so  covered  by  the  long 
head  of  the  triceps ;  but  as  this  head  was  cut,  and  the  limb  hanging, 
its  upper  end,  B,  was  pushed  back  by  the  latissimus  dorsi  arching  in 
front. 

The  latissimus  dorsi,  M,  and  teres  major,  N,  are  stretched  as  they 
descend  to  the  humerus.  Only  the  upper  edge  of  the  teres  appears  ; 
below  and  in  front  they  are  partly  blended  by  tendinous  fibres. 

By  the  weight  of  the  limb  the  deltoid  m.uscle,  P,  is  made  to  look 
flatter  than  it  is  usually. 

*  This  statement  of  the  origin  of  the  inner  and  outer  heads  of  the  triceps  differs 
much  from  the  common  Anatomical  description.  It  contains  the  view  of  Theile, 
and  has  the  merit  of  being  more  accurate.  The  original  account  is  given  in 
Miiller's  Archiv  flir  Anatomie,  etc.,  for  1839,  p.  420—"  Ueber  den  Triceps  brachii 
und  den  flexor  digitorum  sublimis  des  Menschen." 


60 


ILLU8TKATI0XS    OF   DISSECTIONS. 


VESSELS  OF  THE  BACK  OF  THE  AR'M. 

Tlie  ramifications  of  the  superior  profunda  artery  through  the  triceps, 
and  its  origin  from  the  brachial  trunk,  are  contained  in  this  region. 
Some  small  branches  of  the  circumflex  artery  appear  behind  the  border 
of  the  deltoid. 


a.  Brachial  artery. 

6.  Basilic  vein  becoming  axillary. 

c.  Superior  profunda  artery. 

d.  Offset  of  the  profunda  to  the  front 

of  the  arm,  with  the  musculo- 
spiral  nerve. 

/.  Branch  of  artery  along  the  outer 
intermuscular  septum. 

g.  Inosculating  artery  from  the  re- 
current radial. 


h.  Anastomotic  branch  from  the  in- 
terosseous recvirrent  artery. 

h.  Muscular  branch  of  the  arterj-  to 
the  triceps  and  anconeus. 

I.  Branch  of  artery  to  the  teres 
minor  from  the  posterior  circum- 
flex. 

m.  and  n.  Cutaneous  and  muscular 
offsets  of  the  posterior  circum- 
flex artery. 


Brachial  artery,  a. — The  anatomy  of  the  brachial  trunk  issuing  from 
the  armpit  has  been  described  with  Plate  yi.,  p.  56.  The  following  large 
muscular  offset  springs  from  this  part  of  the  artery. 

The  superior  profunda  branch,  c,  is  the  nutritive  and  anastomotic 
vessel  of  the  back  of  the  arm,  and  corresponds  with  the  profunda  artery 
of  the  femoral  trunk  in  the  thigh.  Springing  from  the  brachial,  near 
the  axilla,  it  is  the  largest  offset  of  that  vessel,  and  wind?  behind  the 
humerus  in  the  hollow  separating  the  inner  and  outer  heads  of  the  tri- 
ceps, as  far  as  the  outer  side  of  the  limb,  where  it  ends  in  muscular, 
anastomotic,  and  cutaneous  offsets. 

The  muscular  Iranches  supply  the  three  heads  of  the  triceps,  viz., 
the  long  head.  A,  the  external,  C,  and  the  internal,  D.  A  second  artery 
enters  the  long  head  from  the  brachial  trunk. 

The  anastomotic  offsets,  three  in  number,  spring  from  the  end  of  the 
profunda.  One,  &,  variable  in  size,  accompanies  the  musculo-spiral  nerve 
to  the  front  of  the  arm,  and  communicates  with  the  radial  recurrent.  A 
second,  /,  runs  on  the  intermuscular  septum  to  the  outer  condyle,  and 
anastomoses  with  a  branch,  g,  of  the  radial  recurrent,  and  with  a  branch, 
h,  of  the  recurrent  interosseous  ;  and  the  third  artery,  h,  descends  in  the 
triceps  to  the  hollow  between  the  outer  condyle  and  the  olecranon,  and 


NERVES    OF    THE    BACK    OF    THE    ARM. 


61 


entering  the  anconeus,  G,  joins  in  the  last  muscle  with  the  recurrent  of 
the  interosseous. 

The  cutaneous  offsets,  two  or  three  in  number,  joass  out  with  nerves 
to  the  integuments,  and  are  derived,  for  the  most  part,  from  the 
branch,  /. 

The  posterior'  circumflex  artery  enters  under  the  deltoid  muscle 
(Plate  v.).  From  the  part  of  the  artery  now  visible  spring  the  branch  to 
the  teres  minor,  /,  and  the  offsets  to  the  integuments  and  the  deltoid,  m, 
and  n. 

The  usual  companion  veins  run  with  the  arteries,  though  they  are  not 
included  in  the  Plate;  those  with  the  profunda  artery  join  a  brachial 
vein  ;  and  the  circumflex  veins  open  into  the  axillary  trunk. 


NERVES   OF  THE   BACK   OF  THE   ARM. 

The  nerves  correspond  in  the  mam  with  the  vessels.  With  the 
profunda  is  situate  the  large  musculo-spiral  nerve,  distributing  branches 
to  the  triceps  and  the  integuments ;  and  by  the  side  of  the  circumflex 
artery  lies  the  muscular  nerve  of  the  same  name,  which  ends  in  the 
deltoid. 


1.  Musculo-spiral  nerve. 
2,  2.  Ulnar  nerve. 

3.  Offset  to  the  long  head  of  the 

triceps. 

4.  Offset  to  the  inner  head  of  the 

triceps. 
f  f  f  Three    branches  to  the   outer 
head  of  the  triceps. 


6.  Branch  to  the  anconeus. 

7.  Upper  external  cutaneous  of  the 

musculo-spiral. 

8.  Lower  external  cutaneous  of  the 

musculo-spiral. 

9.  Nerve  to  the  teres  minor, 

10.  Cutaneous  branch  of  the  circum- 
flex nerve. 


The  musculo-spiral  nerve,  1,  begins  in  the  brachial  plexus  (Plate  i. 
13);  and,  reaching  the  digits,  supplies  the  extensor  and  supinator  muscles 
on  the  back  of  the  arm  and  forearm,  together  with  some  of  the  integu- 
ments. 

In  the  arm  the  trunk  winds  behind  the  humerus  from  the  inner  to 
the  outer  side,  and  divides  at  the  outer  condyle  into  two — radial  and 
posterior  interosseous  nerves  (Plate  xii.).  The  nerve  lies  m  the  groove 
of  the  humerus  between  the  inner  and  outer  heads  of  the  triceps,  and 
turns  to  the  front  of  the  arm  above  the  supinator  longus  muscle,  H. 


62  ILLDSTKATIONS    OF    DISSECTIONS. 

Offsets  of  the  part  of  the  nerve  now  dissected  supply  the  extensors  of  the 
elbow-joint  and  the  teguments. 

Muscular  branches  enter  the  heads  of  the  triceps.  One,  3,  belongs  to 
the  parts,  A,  and  B,  of  the  long  head;  others,  4,  and  6,  supply  the  inner 
head,  D;  and  three  f  f  f  enter  the  outer  head,  C.  To  the  inner  and 
long  lieads  some  branches  are  furnished  by  the  trunk  of  the  nerve  in  the 
axilla  (Plate  iv.  2). 

The  branch,  6,  of  the  anconeus  is  very  slender,  and  is  contained  in 
the  triceps. 

Cutaneous  nerves. — Two  external  cutaneous  appear  with  superficial 
arteries  on  the  outside  of  the  limb;  the  ujiper  one,  7,  smaller  than  the 
other,  reaches  in  the  integuments  of  the  arm  as  far  as  the  elbow;  and  the 
lower  nerve,  8,  is  continued  beyond  the  elbow,  on  the  back  of  the  fore- 
arm, nearly  to  the  wrist. 

Whilst  the  musculo-spiral  is  contained  in  the  axilla  it  furnishes  an 
internal  cutaneous  nerve  to  the  inner  and  hinder  parts  of  the  arm  (Plate 
iv.  1). 

If  the  musculo-spiral  nerve  is  cut  across,  or  its  action  much  impaired 
by  disease,  the  extensor  muscles  of  the  elbow-Joint,  amongst  others, 
would  be  incapable  of  contracting;  and  the  elbow  would  therefore  be 
bent  by  the  flexors  which,  being  uncontrolled  by  their  antagonists,  would 
carry  forwards  the  forearm  bones. 

Ulnar  nerve,  2,  2. — The  upper  and  lower  parts  of  this  nerve  come 
into  view  in  the  Figure.  The  whole  course  of  the  nerve  appears  in 
Plate  iv. 

Circumflex  nerve  of  the  shoulder. — ^The  trunk  of  the  nerve  is  noticed 
in  the  description  of  Plate  v.  Two  offsets,  viz.,  one  marked,  9,  for  the 
teres  muscle,  and  another,  10,  for  the  integuments,  appear  behind  the 
deltoid  muscle. 


PLATE  VI 


SUPERFICIAL   MUSCLES   OF    THE   FOREARM. 


63 


DESCRIPTION  OF  PLATE  VIII. 


The  dissection  of  the  muscles,  vessels,  and  nerves  of  the  front  of  the 
forearm,  with  their  connections  undisturbed  by  the  reflection  of  the  deep 
fascia,  is  here  displayed. 

All  the  superficial  coverings  of  the  limb  may  be  removed  at  once  by 
an  incision  along  the  front  of  the  forearm,  met  by  a  cross-cut  a  little 
above  the  elbow,  and  by  another  rather  below  the  wrist.  But  a  more 
profitable  dissection  may  be  made  by  examining,  and  afterwards  remov- 
ing in  successive  layers,  the  skin,  the  subcutaneous  fat  with  its  vessels 
and  nerves,  and  the  deep  fascia. 


SUPERFICIAL    MUSCLES    OF  THE  FOREARM. 

Inside  the  line  of  the  brachial  and  radial  arteries,  1)  and/,  lies  a  group 
of  muscles  which  act  as  flexors  and  pronators;  and  outside  the  vessels  is 
a  mass  of  muscles  consisting  of  extensors  and  supinators,  antagonists  of 
the  former  set. 

The  inner  group  is  divided  into  two  strata,  superficial  and  deep. 
Five  muscles  belong  to  the  superficial  layer:  of  these  one  is  a  pronator 
of  the  hand,  and  the  others  are  flexors  of  the  wrist  and  fingers. 


A.  Biceps  flexor  brachii. 

B.  Brachialis  anticus. 

C.  Pronator  teres. 

D.  Palmaris  longus. 

E.  Flexor  carpi  radialis. 

F.  Flexor  digitorum  sublimis. 

G.  Flexor  carpi  ulnaris. 
H.  Flexor  longus  pollicis. 
L.  Supinator  longus. 

N.  Palmaris  brevis. 


P.  Extensor  carpi  radialis  longior. 

S.  Extensor  ossis  metacarpi  pollicis  ; 
close  alongside  is  the  tendon  of 
the  extensor  primi  internodii 
pollicis. 

f  Inner  intermuscular  septum  of  the 
arm. 

*  Slip  of  fascia  connecting  the  ten- 
don of  the  flexor  carpi  ulnaris 
with  the  annular  ligament. 


Pronator  radii  teres,  C,  the  first  muscle  of  the  inner  group,  arises 


64:  ILHJ8TEATI0XS    OF    DISSECTIOXS. 

in  part  from  the  common  origin;*  from  the  condyloid  ridge  of  the  hume- 
rus; and  from  the  coronoid  process  of  the  ulna  by  a  separate  slip  (Plate 
ix.).  Below  it  is  inserted  into  the  middle  of  the  radius  beneath  the  supi- 
nator longus,  L. 

By  its  outer  edge  the  muscle  bounds  the  hollow  in  front  of  the  elbow, 
and  by  the  other  it  touches  the  flexor  carpi  radialis.  Xear  the  insertion 
the  radial  vessels  rest  on  it. 

When  the  pronator  first  contracts  it  will  roll  the  radius  over  the  ulna, 
pronating  the  hand;  and  acting  still  more,  it  will  bend  the  elbow-joint 
over  which  it  passes. 

The  flexor  carpi  radialis,  E,  having  the  common  origin,  is  continued 
through  a  groove  in  the  os  trapezium  to  be  inserted  chiefly  into  the  base 
of  the  metacarpal  bone  of  the  index  finger,  but  also  by  a  slip  into  the 
metacarpal  bone  of  the  middle  finger. 

The  tendon  of  the  muscle  is  prominent  below  outside  the  middle  line 
of  the  forearm,  and  bounds  internally  a  surface-depression  over  the  radius 
which  contains  the  radial  artery;  it  may  be  taken  as  the  guide  to  that 
vessel. 

After  bending  the  wrist,  the  muscle  will  approximate  the  forearm  to 
the  arm. 

The  palmaris  longus,  D,  has  the  common  origin  between  the  preceding 
and  the  flexor  carpi  ulnaris,  G;  and  its  tendon  piercing  the  aponeurosis 
of  the  limb  near  the  wrist,  ends  in  the  fascia  of  the  palm  of  the  hand, 
after  sending  a  slip  to  join  the  short  muscles  of  the  thumb.  This  muscle 
may  be  absent. 

It  renders  tense  the  palmar  fascia,  and  assists  in  bending  the  elbow 
and  wrist. 

T\q  flexor  carpi  ulnaris,  G,  is  the  most  internal  muscle  of  the  set. 
Attached  to  the  inner  condyle  of  the  humerus,  where  it  blends  with  the 
other  muscles,  and  to  the  posterior  ridge  of  the  ulna  by  an  aponeurosis, 
it  is  inserted  into  the  pisiform  bone,  and  joins  by  offsets  the  annular  liga- 
ment of  the  wrist  and  the  muscles  of  the  little  finger. 

The  outer  edge  of  the  muscle  corresponds  with  a  line  from  the  pisiform 


*  Most  of  the  superficial  muscles  of  the  foreaiin,  on  both  the  front  and  back, 
have  a  common  origin  from  the  fascia  of  tlie  limb,  and  from  a  strong  fibrous 
process  (tendon  of  origin)  which  is  attached  to  the  condyle  of  the  humerus  in  each 
case,  and  sends  pieces  between  the  muscles. 


SUPERFICIAL    MUSCLES    OF    THE    FOREARM.  65 

bone  to  the  inner  condyle  of  the  humerus,  and  there  is  a  surface-groove 
in  the  lower  third  of  the  forearm  over  that  edge.  The  muscle  conceals 
below  the  ulnar  vessels  and  nerve. 

Its  main  action  is  expressed  by  its  name,  but  it  serves  also  as  a  flexor 
of  the  elbow-Joint. 

Tlieflexoi^  digitorum  suUimis,  F,  is  the  deepest  of  the  muscles  of  the 
superficial  layer.  It  is  attached  by  its  thin  outer  edge  to  the  upper  three 
fourths  of  the  shaft  of  the  radius;  higher  still,  to  the  inner  side  of  the 
coronoid  process  of  the  ulna;  and  finally  to  the  lateral  ligament  of  the 
elbow-joint,  and  the  common  tendon  of  origin  of  the  other  muscles.  It 
ends  below  in  four  tendons  for  the  fingers,  which  cross  the  hand,  and  are 
inserted  into  the  middle  phalanges  (Plate  x.). 

The  extent  of  attachment  to  the  radius,  and  the  position  of  the  radial 
vessels  to  it  may  be  noticed  in  the  Drawing.  Only  two  tendons  appear 
on  the  surface,  viz.,  those  of  the  middle  and  ring  fingers.  Issuing 
beneath  the  lower  border  is  the  median  nerve,  2. 

Besides  bending  the  phalanges,  the  muscle  will  contribute  to  flex  the 
wrist  and  elbow. 

Above  the  elbow  are  the  flexors  of  that  joint,  viz.,  biceps  and  hracliialis 
anticus.  The  first  is  inserted  into  the  radius  and  the  other  into  the  ulna; 
and  when  they  contract  they  carry  forwards  those  bones  over  the  end  of 
the  humerus. 

After  fracture  of  the  olecranon  process  of  the  ulna — the  part  limiting 
the  movements  and  giving  security  to  the  joint — the  elbow  is  bent  because 
these  two  muscles  are  stronger  than  the  extensor  muscles  behind  (the 
triceps  being  useless). 

In  dislocation  of  the  humerus  on  the  front  of  the  ulna  and  radius,  the 
flexor  muscles  give  the  bent  state  to  the  limb.  Being  greatly  stretched, 
especially  the  brachialis,  by  the  large  projecting  end  of  the  humerus,  they 
contract  powerfully;  and  the  forearm  is  carried  forwards  as  much  as  it 
can  be  to  relax  the  tense  state  of  the  muscular  fibres. 

The  extensors  and  supinators  on  the  outer  side  of  the  limb  are  dis- 
sected only  in  part:  they  will  be  described  more  fully  with  Plate  xii. 
They  are  divisible,  like  the  muscles  in  front,  into  a  superficial  and  a  deep 
layer.     Only  one  of  them  will  be  referred  to  now. 

ThQ  supinator  longns,  L  (brachio-radialis  Soem.),  is  the  most  anterior 
and  the  longest  of  the  external  group.  It  arises  from  the  upper  two  thirds 
of  the  condyloid  ridge  of  the  humerus  in  front  of  the  outer  intermuscular 


66  ILLUSTRATIONS    OF    DISSECTIONS. 

septum  (Plate  xii.);  and  it  is  inserted  into  the  lower  end  of  the  radius, 
close  to  the  styloid  process. 

Covered  at  its  origin  and  insertion  by  other  muscles,  it  forms  part  of 
the  outer  swell  of  the  forearm,  and  limits  externally  the  hollow  in  front 
of  the  elbow- joint.  It  rests  upon  the  long  radial  extensor  of  the  wrist, 
P,  and  covers  the  radial  artery  in  the  upper  half  of  the  forearm.  At  its 
insertion  it  is  crossed  by  the  extensor  muscles  of  the  thumb,  S. 

Its  chief  office  is  to  bend  the  elbow-joint.  But  it  will  become  a  supi- 
nator when  the  hand  is  quite  prone;  and,  Avhen  the  hand  is  strongly 
supinated,  it  is  said  to  bring  the  same  into  the  prone  position. 


HOLLOW   IX  FRONT   OF  THE  ELBOW. 

This  intermuscular  space  between  the  inner  and  outer  groups  of  mus- 
cles is  represented  in  the  lower  limb  by  the  ham.  It  contains  the  chief 
vessel  of  the  arm  and  the  companion  nerve;  and  by  its  position  on  the 
aspect  of  the  limb  to  which  the  joint  is  bent,  greater  freedom  of  move- 
ment forwards  is  permitted. 

The  interval  is  somewhat  triangular  in  form,  as  seen  on  the  surface, 
and  has  the  following  boundaries: — stretching  over  it  is  the  aponeurosis 
of  the  limb  joined  by  an  offset  from  the  biceps  tendon,  with  the  integu- 
ments and  the  superficial  veins  and  nerves  (Plate  iii.);  and  covering  the 
underlying  bones  are  the  brachialis  anticus,  B,  and  supinator  brevis. 
Externally  is  placed  the  supinator  longus,  L,  and  internally  the  pronator 
teres,  C;  the  fibres  of  the  former  being  nearly  straight  in  the  forearm, 
and  those  of  the  latter  slanting  downw\ards  and  outwards.  The  base  is 
turned  towards  the  arm;  and  the  apex  points  forwards  in  the  forearm. 

Contained  in  the  hollow  is  the  tendon  of  the  biceps,  with  vessels, 
nerves,  fat,  and  lymphatics;  and  their  position  in  it  is  as  follows: — 

On  the  outer  side  is  the  biceps  muscle.  A,  whose  tendon  dips  into 
the  space  to  reach  its  insertion  into  the  radius. 

The  brachial  artery,  I,  lies  close  inside  the  biceps,  and  divides,  oppo- 
site the  ''neck  of  the  radius  "  (Quain),  into  the  two  arteries  of  the  fore- 
arm, which  are  directed  forwards  through  the  space,  the  radial  being 
superficial  and  the  ulnar  deep  in  its  position.  ense  comites  entwine 
around  the  arterial  trunks.  Small  arteries  are  found  in  the  space.  Thus 
in  the  outer  part  the  recurrent  of  the  radial  artery  (Plate  xii.  3)  is  di- 


AKTEKIES   OF   THS   FOREARM. 


67 


rected  transversely  to  the  supinator  longus;  and  in  the  inner  part  of  the 
hollow,  offsets  of  the  anastomotic  artery,  a,  descend  beneath  the  pronator 
teres  to  join  the  anterior  recurrent  of  the  ulnar  artery.  Other  cutaneous 
offsets,  c  and  d,  come  forwards  to  the  integuments  from  the  brachial  and 
the  radial  artery. 

Inside  the  artery,  and  separated  from  it  by  a  slight  interval,  which 
increases  below  to  a  quarter  or  half  an  inch,  comes  the  median  nerve,  2. 
At  this  spot  the  nerve  supplies  small  offsets  to  the  inner  group  of  muscles 
of  the  forearm.  Underneath  the  supinator  longus,  and  therefore  outside 
the  superficial  limits  of  the  space,  the  musculo-spiral  nerve  may  be  found 
dividing  in  front  of  the  condyle  of  the  humerus  into  radial  and  posterior 
interosseous  branches. 

Loose  fat  fills  the  hollow,  supporting  the  vessels  and  nerves,  and  ex- 
tends into  the  forearm  along  the  bloodvessels;  and  blood  effused  beneath 
the  fascia  finds  its  way  along  the  same  channels. 

A  few  lympathic  glands  with  their  connecting  vessels  accompany  the 
arteries — two  or  three  lying  on  the  sides  of  the  brachial,  and  one  below 
its  jioint  of  splitting. 

From  the  lax  condition  of  the  parts  surrounding  the  brachial  artery 
pressure  applied  to  the  vessel,  when  wounded,  should  be  firm  and  grad- 
uated. The  limb  too  should  be  kept  still;  for  when  the  elbow  is  moved 
much  the  vessel  may  slip  away  from  the  compressing  pad,  and  blood  may 
be  effused  beneath  the  fascia. 


ARTERIES   OF  THE  FOREARM. 

Two  chief  vessels  occupy  the  front  of  the  forearm,  and  these  spring 
from  the  division  of  the  brachial  trunk.  They  are  named  radial  and 
ulnar  from  their  position  in  the  limb;  and  both  reach  the  palm  of  the 
hand,  where  they  form  arches  and  supply  branches  to  the  fingers.  Both 
are  placed  deeper  near  the  elbow  than  at  the  wrist. 


a.  Anastomotic    branch    of    the 

brachial  trunk. 

b.  End  of  the  brachial  artery. 

c,  d.  Unnamed  cutaneous  offsets: 
the  former  from  the  bra- 
chial, and  the  latter  from 
the  radial  arteiy. 


/.   Radial  artery. 
g.   Superficial  volar  branch. 
h.   Ulnar  artery. 

n.   Cutaneous  median  vein,  joining 
a  deep  companion  vein. 


68  ILLUSTRATIONS    OF   DISSECTIONS, 

The  radial  artery,/,  is  the  more  external  of  the  two  bloodvessels  in 
the  forearm,  and  inclines  from  the  bifurcation  of  the  brachial  trunk  to 
the  lower  end  of  the  radius;  it  then  winds  to  the  back  of  the  wrist  be- 
low the  radius,  and  enters  the  hand.  The  part  from  the  wrist  onwards 
will  be  included  in  other  dissections  (Plates  x.  and  xi. ).  A  line  from 
the  centre  of  the  elbow-joint  to  the  styloid  process  of  the  radius  will 
mark  the  course  of  the  vessel  on  the  front  of  the  forearm. 

In  the  upper  half  of  the  forearm  the  artery  is  concealed  by  the  supi- 
nator longus;  *  and  it  rests  in  succession  on  the  supinator  brevis,  pronator 
teres,  C,  and  flexor  sublimis  digitorum,  F. 

Venae  comites  lie  on  the  sides  of  the  artery.  But  no  nerve  is  in  con- 
tact with  it — the  radial  being  placed  too  far  out. 

This  part  of  the  artery  may  be  superficial  to  the  long  supinator,  lying 
even  in  the  integuments,  when  there  is  an  unusual  origin  from  the 
brachial. 

In  the  lower  half  of  the  forearm  the  vessel  is  not  covered  by  muscle, 
but  is  contained  in  a  hollow  between  the  tendons  of  the  flexor  carpi  radi- 
alis,  E,  and  supinator  longus,  L.  Only  the  common  teguments  cover 
the  vessel  here.  It  is  supported  by  part  of  the  flexor  sublimis,  F,  flexor 
longus  pollicis,  H,  and  lower  down  by  the  pronator  quadratus  and  the 
end  of  the  radius. 

The  usual  veins  surround  the  artery.  The  radial  nerve,  3,  is  at  some 
little  distance  outside  the  vessel,  and  becomes  cutaneous  behind  the  ten- 
don of  the  supinator  longus. 

The  of  sets  of  the  radial  artery  are  for  the  most  part  small,  but  near 
the  elbow  and  wrist  they  acquire  greater  size.  No  one  is  large  enough 
usually  to  interfere  with  the  placing  a  ligature  on  the  trunk. 

Ligature  of  the  radial  artery. — In  the  upper  half  the  vessel  would  not 
require  to  be  tied  in  the  living  body  unless  it  was  wounded.  In  seeking 
it  amongst  the  tissues  infiltrated  with  blood  the  supinator  longus,  and  the 
line  of  the  vessel,  will  serve  as  material  aids  to  the  surgeon. 

In  the  lower  third  of  the  forearm,  the  radial  may  be  secured  for  a 


*  In  Anatomical  Plates  the  radial  artery  is  usually  delmeated  with  the  supi- 
nator longus  removed  from  it,  as  if  the  vessel  was  uncovered  by  muscle  in  the 
upper  half  of  the  forearm.  In  this  Plate  the  muscle  is  shown  covering  the  ar- 
tery, as  it  exists  before  it  is  displaced,  to  impress  upon  the  memory  the  fact  that 
where  the  radial  is  so  protected  it  cannot  be  easily  injured. 


ARTERIES    OF   THE   FOREARM.  69 

wound  in  the  palm  of  the  liand.  AVith  a  cut  about  one  inch  and  a  half 
long  the  integuments  and  superficial  veins  and  nerves  are  to  be  divided 
in  the  line  of  the  vessel.  The  fascia  may  be  carefully  cut  for  the  same 
extent.  After  the  sheath  has  been  opened  and  separated  from  its  con- 
tents in  the  usual  way,  the  aneurism  needle  may  be  carried  round  the 
artery. 

As  this  part  of  the  radial  is  so  superficial  the  student,  when  first  prac- 
tising the  operation,  cuts  oftentimes,  not  only  the  coverings  of  the  limb, 
but  also  the  artery. 

If  the  vessel  is  tied  for  a  wound  near  the  wrist  two  ligatures  should  be 
applied,  although  the  size  is  so  small,  on  account  of  the  free  communica- 
tion of  the  radial  with  the  ulnar  artery  in  the  palm  of  the  hand. 

Brandies  of  tlie  artery. — Small  unnamed  muscular  and  cutaneous  off- 
sets leave  the  trunk  of  the  artery  at  intervals;  and  larger  named  branches 
arise  near  the  beginning  and  ending. 

The  recurrent  radial  ascends  under  cover  of  the  supinator  longus, 
and  anastomoses  on  the  outer  part  of  the  elbow  with  the  superior  pro- 
funda (Plate  xii.):  it  supplies  some  of  the  outer  group  of  muscles. 

The  superficial  volar  hrancli,  g,  descends  to  the  hand  across  or 
through  the  short  muscles  of  the  thumb.  When  small,  it  ends  in  those 
muscles  (Quain);  and  when  larger,  it  joins  the  superficial  palmar  arch 
(Plate  X.).  With  this  vessel  of  very  unusual  size  a  wound  of  it  might 
require  it  to  be  tied. 

The  anterior  carpal  branch  (Plate  ix.  d),  which  is  generally  so 
small  as  not  to  deserve  notice,  arises  near  the  wrist,  and  is  lost  on  the 
carpus. 

Muscular  and  cutaneous  branches  arise  at  tolerably  regular  intervals. 
One  to  the  integuments  is  marked  by  c.  From  a  muscular  branch  near 
the  wrist  a  twig  entered  the  median  nerve. 

The  ulnar  artery,  h,  is  concealed  almost  entirely  by  muscles  whilst  it 
is  in  the  forearm,  only  a  small  part  near  the  wrist  being  visible  before  the 
natural  position  of  the  flexor  carpi  ulnaris  has  been  disturbed.  *  And  the 
part  of  the  artery,  which  is  represented,  appears  smaller  than  it  is  com- 

*  In  Plates  of  the  vessels  of  the  forearm,  where  the  ulnar  artery  is  laid  bare 
to  view  in  the  lower  third  or  more,  the  flexor  carpi  ulnaris  has  been  drawn  aside 
in  the  dissection.  This  rather  deep  condition  of  the  artery  should  be  kept  in  mind 
in  any  attempt  to  put  a  ligature  on  it. 


70 


ILLUSTRATIONS    OF    DISSECTIONS. 


monly,  in  consequence  of  being  partly  covered  by  the  venae  comites. 
The  course  and  the  branches  of  the  artery  were  shown  in  Plate  ix. 


NERVES   OF  THE  FOREARM. 

Three  nerves,  viz.,  median,  ulnar,  and  radial,  are  visible  each  for  a 
short  distance  in  this  dissection  of  the  superficial  muscles  of  the  forearm. 


1.  Cutaneous  part  of  the  musculo- 
cutaneous,  named    external 
cutaneous  of  the  forearm. 
2,  3.  Median  nerve. 


3.  Radial  nerve. 

4.  Cutaneous  palmar  branch  of  the 

median  nerve. 

5.  Palmar  part  of  the  ulnar  nerve. 


The  median  nerve,  2,  is  superficial  for  two  inches  above  the  wrist, 
and  is  placed  on  the  outer  side  of  the  tendons  of  the  flexor  sublimis.  As 
it  passes  through  the  forearm  it  lies  beneath  the  superficial  flexors. 
From  the  forearm  it  is  continued  to  the  hand  beneath  the  annular  liga- 
ment.    The  following  offset  arises  from  this  part  of  the  nerve. 

The  cutaneous  ijalmar  Irancli,  4,  pierces  the  deep  fascia  near  the 
wrist,  and  crosses  over  the  annular  ligament  to  end  in  the  integuments 
of  the  ball  of  the  thumb  and  palm  of  the  hand;  at  its  ending  it  commu- 
nicates with  the  ulnar  nerve. 

The  radial  nerve,  3,  is  a  tegumentary  branch  of  the  musculo-spiral 
(Plate  xii.  2),  and  ends  on  the  back  of  the  hand.  Becoming  superficial 
behind  the  tendon  of  the  supinator  longus,  it  terminates  in  the  tegu- 
ments of  the  back  of  the  thumb,  of  the  next  two  digits,  and  sometimes 
of  half  the  ring  finger. 

The  ulnar  nerve,  5,  enters  the  palm  of  the  hand  over  the  annular 
ligament;  its  termination  is  given  in  Plate  x.  This  is  the  only  part  of 
the  nerve  which  comes  into  sight  in  the  forearm  before  the  flexor  carpi 
ulnaris  has  been  turned  aside;  and  it  is  partly  concealed  by  the  ulnar 
vessels. 


PLATE  IX, 


.V 


DEEP  .MUSCLES    OF    THE   FOREARM. 


n 


DESCRIPTION  OF  PLATE  IX. 


This  Plate  represents  the  dissection  of  the  deep  muscles  on  the  front 
of  the  forearm,  with  the  vessels  and  nerves  in  contact  with  them. 

•  To  make  ready  the  dissection  cut  through  near  the  humerus  and 
remove  the  inner  group  of  the  superficial  muscles,  seen  in  Plate  viii., 
except  the  pronator  teres  on  the  outside,  and  the  flexor  carpi  ulnaris 
on  the  inside;  then  draw  upwards  the  pronator,  and  inwards  slightly  the 
flexor  nlnaris  from  the  ulnar  vessels.  The  small  veins  with  the  branches 
of  the  arteries  have  been  taken  away. 

DEEP  MUSCLES  OF  THE  FOREARM. 

The  deep  muscles  are  three  in  number:  two  flex  the  digits,  and  one 
pronates  the  radius.  One,  a  flexor  of  the  thumb,  lies  on  the  radius;  and 
the  other  large  muscle,  covering  the  ulnar,  is  the  common  flexor  of  the 
fingers.     The  pronator  is  placed  beneath  the  other  two  near  the  wrist. 


A.  Lower  end  of  the  biceps. 

B.  Brachialis  anticus. 

C.  Supinator  longus. 

D.  Pronator  teres. 

F.  Conjoined  palmaris  longus  and 

flexor  carpi  radialis,  cut,  and, 
turned  aside. 

G.  Flexor  carpi  ulnaris. 
H.  Supinator  brevis. 

J.  Cut  end  of  the  flexor  sublimis. 


K.  Flexor  longus  poilicis. 
L.  Flexor  profundus  digitorum. 
N.  Slip  of  flexor  longus  poilicis. 
O.  Extensor  ossis  metacarpi  poilicis. 
P.  Pronator  quadratus  muscle. 
Q.  Tendons  of  flexor  sublimis,  cut. 
R.  Tendon  of  flexor  carpi  radialis. 
X.  Anterior  annular  ligament, 
f     Internal  intermuscular  septum  of 
the  arm. 


The  flexor  longus  poilicis,  K,  arises  from  the  upper  three  fourths  of 
the  anterior  surface  of  the  shaft  of  the  radius;  from  the  contiguous  in- 
terosseous membrane;  and  sometimes  by  a  round  slip,  N,  from  the  inner 
part  of  the  coronoid  process  of  the  ulna.  Its  tendon  passes  beneath  the 
annular  ligament,  X,  and  is  conveyed  along  the  thumb  by  a  fibrous  sheath 
to  be  inserted  into  the  last  phalanx. 


T2  ILLUSTRATIONS    OF    DISSECTIONS. 

Most  of  the  muscle  is  covered  by  the  flexor  sublimis,  b.ut  part  of  it  be- 
low is  in  contact  with  the  radial  artery  where  the  pulse  is  felt.  Between 
the  upper  attachments  of  this  muscle  and  the  supinator  brevis,  H,  to  the 
radius,  is  a  narrow  slip  of  the  bone  from  which  the  flexor  sublimis  digi- 
toi'um  arises. 

The  muscle  bends  the  phalanges  of  the  thumb,  and  brings  the  meta- 
carpal bone  towards  the  palm  of  the  hand.  It  will  flex  the  wrist  after 
the  digit. 

Flexor  profundus  digitorum,  L  (perforans).  It  arises  from  the  an- 
I'erior  and  inner  surfaces  of  the  shaft  of  the  ulna  as  low  as  the  pro- 
nator quadratus;  and  other  fibres  spring  from  the  membranes  outside 
and  inside  the  bony  attachment,  viz.,  from  the  interosseous  membrane 
externally,  and  from  an  aponeurosis  common  to  this  muscle  and  the  flexor 
■carpi  ulnaris  internally.  The  fleshy  fibres  end  in  tendons  which  are 
united  together  above  the  wrist,  only  the  most  external  being  separate; 
.and  these,  passing  beneath  the  annular  ligament,  X,  and  across  the  hand, 
are  inserted  into  the  last  phalanges  of  the  fingers.     See  Plate  x. 

On  the  sides  of  the  muscle  are  the  flexor  longus  pollicis,  K,  and  flexor 
carpi  ulnaris,  G.  On  it  rest  the  ulnar  vessels,  and  the  ulnar  and  median 
nerves. 

This  muscle  bends  the  last  phalanx  of  each  finger;  and  continuing  its 
.action  it  will  aid  in  flexing  the  other  phalanges  and  the  wrist. 

The  pronator  quadratus,  P,  lies  beneath  the  preceding,  and  covers 
the  lower  ends  of  the  bones  of  the  forearm  for  about  two  inches,  though 
more  of  the  ulna  than  of  the  radius.  Scarcely  any  part  of  the  muscle  is 
seen,  but  the  interosseous  nerve  and  artery  pass  beneath  its  upper  edge, 
marking  its  extent  upwards. 

It  is  covered  by  the  other  two  muscles  of  the  deep  layer,  and  the  radial 
iressels  touch  the  outer  edge,  near  the  wrist. 

It  acts  on  the  radius,  moving  the  lower  end  round  the  ulna  so  as  to 
put  down  the  palm  of  the  hand. 

Movement  of  the  radius. — The  rotatory  motion  of  the  hand  is  due  to 
the  movement  forwards  and  backwards  of  the  lower  end  of  the  radius 
over  the  ulna.  When  that  bone  is  brought  forwards  the  palm  of  the 
hand  is  placed  down,  or  the  limb  is  pronated ;  and  when  the  bone  is 
moved  back  the  dorsum  of  the  hand  is  turned  towards  the  gi'ound,  and 
the  member  is  supinated.  The  pronator  muscles  are  in  front,  and  pass- 
ing from  the  inner  side  of  the  limb,  draw  forwards  the  radius  ;  while  the 


FEACrUKE    OF   THE    RADIUS.  73 

supinators,  which  turn  back  the  bone,  are  phiced  on  both  the  front  and 
hinder  part  of  the  limb.  The  action  of  the  supinators  will  be  given  with 
the  description  of  Plate  xii. 

Two  pronators  are  connected  with  the  radius  ; — one,  pronator  teres  of 
the  superficial  layer,  being  attached  about  midway  between  the  ends ; 
and  the  other,  pronator  quadratus,  of  the  deep  layer,  is  fixed  into  the 
lower  part.  Both  are  therefore  inserted  below  the  upper  half  of  the 
bone  ;  and  during  their  contraction  the  lower  end  of  the  radius  is  moved 
over  the  ulna — the  u]iper  end  not  changing  its  position  to  that  bone,  but 
rotating  in  its  band  like  a  wheel.  And  as  the  active  supinators  (supinator 
brevis  and  biceps)  are  fixed  to  the  upper  part  of  the  radius,  their  influence 
on  the  lower  end  is  neutralized  as  soon  as  the  bone  is  broken  through  at 
or  near  the  middle  ;  so  that  the  lower  fragment  can  be  then  moved  for- 
wards without  obstacle  by  the  action  of  the  pronators. 

Fracture  of  the  radius  near  or  below  the  middle  is  attended  by  prona- 
tion of  the  hand,  and  by  displacement  of  the  lower  fragment,  in  conse- 
quence of  the  action  of  one  or  both  of  the  pronators,  and  of  the  weight 
of  the  hand  articulated  to  the  radius.  But  the  upper  fragment  of  the 
broken  bone  does  not  change  its  place  ;  it  remains  on  the  outer  side  of 
the  ulna,  though  tilted  away  from  that  bone  by  the  action  of  the  supina- 
tors. Keadjustment  of  the  displaced  lower  fragment  will  be  made  by 
supinating  the  hand,  for  this  movement  carries  back  at  the  same  time  the 
lower  end  of  the  broken  radius  into  contact  with  the  uj)per.  Future 
displacement  of  the  lower  fragment  will  be  prevented  if  the  weight  of  the 
hand  is  taken  off  by  fixing  the  forearm  and  hand  with  splints  in  a  posi- 
tion midway  between  pronation  and  supination,  so  that  the  thumb  shall 
be  in  a  line  with  the  upper  part  of  the  radius,  and  the  palm  of  the  hand 
shall  be  turned  to  the  chest. 

Should  the  lower  fragment  not  be  brought  well  into  line  with  the 
upper  by  the  position  of  the  forearm  above-said,  it  will  be  necessary  to 
place  the  hand  quite  supine  (the  palm  of  the  hand  looking  directly 
upwards),  and  to  fix  it  with  splints  in  that  posture,  as  was  recommended 
by  Mr.  Lonsdale.  * 

\n  fracture  of  the  shafts  ofhoth  hones  of  the  forearm,  the  lower  ends, 
as  in  fracture  of  the  radius,  de|)art  from  the  line  of  the  upper  ends,  being 

*  "Fracture  of  the  Forearm."  By  Edward  Lonsdale.  Medical  Gazette,  1832, 
p.  910. 


74 


ILLUSTRATIONS    OF    DISSECTIONS. 


dragged  away,  by  the  weight  of  the  hand.  They  have  further  a  tendency 
to  approximate  across  the  interosseous  space,  and  will  therefore  be 
easily  made  to  touch  by  any  constriction,  such  as  a  bandage  round  the 
limb. 

By  supinating  the  hand  in  the  manner  described  for  fracture  of  the 
radius,  the  lower  displaced  ends  will  be  brought  to  the  upper  fixed  jiiivts 
of  the  bones.  And  with  the  view  of  keeping  apart  the  bones,  gentle 
jDressure  with  a  narrow  graduated  pad  is  sometimes  employed  along  the 
front  and  back  of  the  forearm  in  a  line  with  the  interval  between  them. 
Pressure  by  means  of  a  bandage  is  not  to  be  made  on  the  member,  lest 
the  broken  ends  be  brought  together,  and  the  movements  of  the  radius 
be  lost  by  this  bono  blending  with  the  ulna  in  the  process  of  union.  Ee- 
displacement  of  the  apposited  ends  may  be  prevented  by  splints  reaching 
from  the  elbow  to  the  fingers. 


ARTERIES  OF  THE  FOREARM. 

Both  radial  and  ulnar  arteries  are  laid  bare  in  the  dissection,  but  the 
anatomy  only  of  the  ulnar  and  its  branches  will  be  now  given.  For  a 
short  distance  above  the  elbow-joint  the  brachial  trunk  is  shown. 


a.  Brachial  artery. 

b.  Radial  artery. 

c.  Ulnar  artery. 

d.  Anterior   carpal  branch  of    the 

radial  trunk. 


e. '  Superficial  volar  branch. 

g.  Posterior  ulnar  recurrent  branch. 

k.  Anterior  interosseous. 

n.  Median  artery. 


The  ulna7-  artery,  c,  tends  to  the  inner  side  of  the  limb,  and  enters 
the  palm  of  the  hand  in  front  (Plate  x.).  It  keeps  the  name  "ulnar" 
from  the  bifurcation  of  the  brachial  trunk  to  the  lower  border  of  the 
annular  ligament,  X.' 

The  artery  has  a  curved  course  in  the  forearm,  being  directed  inwards 
in  the  upper  part,  but  taking  a  straight  direction  at  the  lower  part.  A 
line  on  the  surface,  to  mark  the  straight  part  of  the  artery,  should  be 
drawn  from  the  inner  condyle  of  the  humerus  to  the  inner  side  of  the 
pisiform  bone.  The  vessel  is  covered  by  muscles  in  the  upper  half  of  the 
forearm,  but  becomes  more  superficial  below. 

In  the  deep  part  of  its  course,  viz.,  between  the  origin  and  the  meet- 


ARTERIES    OF   THE   FOREARM.  75 

ing  with  the  flexor  carpi  nhiaris,  G,  the  artery  is  curved  with  the  con- 
vexity upwards.  It  is  covered  by  the  superficial  layer  of  muscles  except 
the  flexor  carpi  ulnaris  ;  and  it  rests  firstly  on  the  lower  part  of  the 
brachialis  anticus,  B,  and  afterwards  on  the  flexor  profundus  digito- 
rum,  L. 

Companion  veins  are  ranged  on  its  sides,  with  communicating  branches 
over  it. 

The  median  nerve,  1,  is  placed  inside  the  ulnar  artery  for  about  an 
inch  ;  it  then  crosses  over,  and  leaves  that  vessel  in  the  forearm.  The 
ulnar  nerve,  3,  approaches  the  artery  about  half  way  between  the  wrist 
and  elbow-Joints,  from  which  point  it  is  situate  inside,  and  close  to  the 
vessel. 

The  loioer  half  of  the  artery  lies  along  the  flexor  carpi  ulnaris,  Gr,  by 
which  it  is  overlapped  (Plate  viii.);  and  it  is  therefore  more  deeply  placed 
than  the  corresponding  part  of  the  radial  bloodvessel.  On  its  outer  side 
are  the  tendons  of  the  flexor  sublimis  digitorum,  F  (Plate  viii.),  and  it 
lies  on  the  flexor  digitorum  profundus,  L. 

The  companion  veins  join  together  freely  over  the  artery,  and  the 
ulnar  nerve,  3,  is  in  contact  with  it  on  the  inner  side.  Filaments  of  the 
palmar  cutaneous  branch,  6,  of  the  ulnar  nerve  entwine  around  the 
vessel. 

As  the  artery  rests  on  the  annular  ligament  of  the  wrist,  it  is  very 
near  the  pisiform  bone ;  it  is  crossed  by  a  slip  from  the  flexor  carpi 
ulnaris  to  the  annular  ligament,  and  is  concealed  by  some  fleshy  bundles 
of  the  palmaris  brevis  muscle  (Plate  viii.).  The  nerve,  still  internal, 
intervenes  between  the  bone  and  the  bloodvessel. 

All  the  offsets  of  the  lower  part  are  too  small  to  be  considered  of 
moment  in  ligature  of  the  artery. 

Ligature  of  the  artery  at  its  toiver  fourth,  which  is  sometimes  prac- 
tised for  a  wound  of  the  trunk  in  the  palm  of  the  hand,  is  a  simple  opera- 
tion ;  and  an  inspection  of  Plate  viii.  will  render  more  intelligible  the 
following  remarks. 

Drawing  back  the  inner  part  of  the  hand  so  as  to  stretch  and  depress 
the  tendon  of  the  flexor  carpi  ulnaris,  make  a  cut  about  two  inches  long 
in  the  hollow  observable  on  the  surface,  and  carry  it  through  the  integu- 
ments and  the  deep  fascia  down  to  the  flexor  tendon.  By  bending  now 
the  wrist,  the  tendon  will  be  relaxed,  and  can  be  moved  aside.  Under 
the  muscle,  but  covered  by  a  deeper  layer  of  fascia,  which  is  to  be  diyided. 


76  ILLU8TKATI0NS    OF   DISSECTIONS. 

the  vessels  and  nerve  will  appear — the  nerve  being  internal  and  serving  as 
the  deep  guide  to  the  artery. 

When  the  sheath  has  been  opened,  and  the  artery  detached  from  it 
and  the  surrounding  veins,  the  needle  carrying  the  ligature  can  be  passed 
easily  under  the  vessel. 

In  tying  the  vessel  for  a  wound  near  the  wrist  two  ligatures  are  to  be 
used,  as  in  the  radial  artery,  because  blood  may  be  poured  out  above  and 
below. 

Branches.  Named  offsets  arise  near  the  large  joints  of  the  wrist  and 
elbow,  and  smaller  muscular  branches  leave  the  trunk  at  short  intervals. 

The  posterior  recurrent  Iranch,  g,  is  continued  beneath  the  super- 
ficial layer  of  muscles  to  the  space  between  the  inner  condyle  of  the 
humerus  and  the  olecranon  process,  where  it  supplies  the  joint,  and 
communicates  with  the  inferior  i^rofunda  and  anastomotic  branches 
(Plate  i v.). 

Xear  the  beginning,  u  small  branch,  anterior  ulnar  recurrent,  ascends 
under  the  joronator  teres  to  join  the  anastomotic  branch. 

The  interosseous  artery  arises  near  the  preceding,  and  divides  into 
two,  anterior  and  posterior,  lor  the  front  and  back  of  the  limb.  The 
posterior  is  seen  in  Plate  xii. 

The  anterior  interosseous,  Tc.  runs  on  the  interosseous  membrane 
between  the  two  deep  flexors  as  far  as  the  pronator  quadratus,  P,  where 
it  passes  through  the  membrane  to  end  on  the  back  of  the  wrist  (Plate 
xii.):  as  the  artery  leaves  the  front  of  the  limb  it  sends  a  branch  on  the 
interosseous  membrane  to  the  fore  part  of  the  wrist. 

It  supplies  branches  to  the  deep  muscles.  Another  offset  median,  n, 
ends  in  the  median  nerve  and  the  flexor  sublimis  muscle:  sometimes  this 
last  branch  is  large,  and  is  continued  with  the  nerve  to  join  the  j)almar 
arch  in  the  hand. 

A  metacarpal  branch  proceeds  along  the  inner  edge  of  the  metacarpal 
bone  of  the  little  finger,  on  which  it  ends. 

A  small  anterior  carpal  branch  takes  origin  opposite  the  lower  edge 
of  the  pronator  quadratus:  it  joins  the  corresponding  branch  of  the  radial 
artery. 

Some  cutaneous  offsets  pass  forwards  to  the  integuments  at  the  outer 
edge  of  the  flexor  carpi  ulnaris :  three  of  these  may  be  observed  in  Plate 
viii. 


NERVES   OF   THE    FOREARM. 


77 


NERVES    OF    THE    FOREARM. 

The  median  and  nlnar  nerves  supply  the  muscles  on  tlie  front  of  the 
forearm,  Avhilst  the  integuments  receive  nerves  mostly  from  other  trunks. 
The  two  have  a  marked  difference  in  position  when  entering  and  leaving 
the  forearm:  thus  above,  the  median  is  superficial  m  front  of,  and  the 
ulnar  is  behind  the  elbow;  but  below,  the  median  is  deeply  placed  beneath 
the  annular  ligament,  whilst  the  ulnar  passes  over  the  ligament. 


1 .  Trunk  of  the  median  nerve. 

2.  Anterior  interosseous  branch. 

3.  Ulnar  nerve. 

4.  Branches  of  ulnar  nerve  to  flexor 

carpi  ulnaris  muscle. 


5.  Branch  of  ulnar  nerve  to  flexor 

digitorum  profundus. 

6.  Cutaneous  palmar  branch  of  the 

ulnar. 

7.  Palmar  cutaneous    nerve    of    the 

median. 


The  median  nerve,  1,  courses  between  the  superficial  and  deep  layers 
of  muscles,  till  about  two  inches  above  the  wrist  where  it  approaches  the 
surface  (Plate  viii.).  It  distributes  nerves  to  all  the  superficial  muscles 
except  the  flexor  carpi  ulnaris,  and  offsets  of  its  interosseous  branch  suj)- 
ply  the  deep  muscles. 

Muscular  offsets  may  be  seen  entering  the  pronator  teres,  D,  the  pal- 
maris  longus,  and  flexor  carpi  radialis,  F,  and  the  flexor  sublimis,  J. 

The  anterior  interosseous  hranch,  2,  runs  on  the  front  of  the  interos- 
seous membrane,  with  the  artery  of  the  same  name,  between  or  in  the 
fibres  of  the  flexors  of  the  digits,  and  ends  below  in  the  pronator  quadra- 
tus,  P.  It  supplies  the  outer  half  of  the  flexor  digitorum  profundus, 
and  the  whole  of  each  of  the  other  two  deep  muscles,  viz.,  flexor  pollicis, 
and  pronator  quadratus. 

The  cutaneous  palmar  irancli,  7,  arises  near  the  wrist:  it  is  described 
with  Plate  viii. 

The  ulnar  nerve,  3,  is  directed  through  the  forearm  along  the  flexor 
carpi  ulnaris  muscle,  in  the  position  of  a  line  from  the  inner  condyle  of 
the  humerus  to  the  pisiform  bone.  Branches  are  supplied  to  one  muscle 
and  a  half. 

Articular  filaments.  Behind  the  elbow  one  or  two  slender  twigs  are 
furnished  to  the  joint. 


78  ILLCSTKATIONS    OF    DISSECTIONS. 

Muscular  offsets.  One  or  two  nerves,  4,  enter  the  flexor  carpi  ulnaris; 
and  one,  5,  belongs  to  the  inner  half  of  the  flexor  digitorum  profundus. 

The  palmar  cutaneous  hrancli,  6,  is  conveyed  along  the  lower  half  or 
third  of  the  ulnar  artery  to  the  integuments  of  the  palm  of  the  hand:  it 
sends  offsets  around  the  artery,  and  communicates  with  the  palmar  branch 
of  the  median  nerve  at  its  ending. 


DESCRIPTION  OF  PLATE  X. 


Views  of  the  two  dissections  of  the  palm  of  the  hand,  which  are 
needed  to  lay  bare  the  superficial  and  dee|)  muscles,  vessels,  and  nerves. 

Figure  1. 

In  the  left-hand  Figure  the  superficial  palmar  arch  of  the  ulnar 
artery,  with  its  offsets,  also  the  nerves  to  the  digits,  and  the  tendons  of 
the  flexor  muscles,  are  delineated. 

In  making  the  dissection  the  integuments  and  the  deep  palmar  fascia 
are  first  to  be  removed.  The  former  may  be  raised  by  a  cut  along  the 
centre  of  the  palm,  terminated  by  cross  cuts  at  the  wrist  and  the  roots  of 
the  fingers ;  and  as  the  inner  flap  is  raised,  the  palmaris  brevis  muscle 
will  be  met  with  in  the  fat.  After  the  palmar  fascia  has  been  denuded, 
and  its  arrangement  at  the  fingers  examined,  it  may  be  cut  behind, 
where  it  joins  the  tendon  of  the  palmaris  longus,  E,  and  may  be  thrown 
forwards. 

By  taking  away  the  teguments  of  one  finger,  say  the  middle,  the 
sheaths  of  the  flexor  tendons  will  come  into  view;  and  after  the  removal 
of  the  sheath,  the  arrangement  of  the  tendons  will  be  manifest,  as  in  the 
ring  finger. 


PLATE  X 


CENTRAL    MUSCLES   OF   THE   PALM.  79 


CENTRAL  MUSCLES  OF  THE  PALM. 

Ill  the  hollow  of  the  hand  lie  the  flexor  tendons,  with  some  other 
muscles.  Laterally  the  muscles  of  the  thumb  and  little  finger  form  on 
each  side  a  ball  or  prominence,  to  be  noticed  afterwards;  and  the  group 
on  the  inner  side  is  partly  covered  by  the  small  subcutaneous  palmar 
muscle. 


A.  Palmaris  brevis. 

B.  Abductor  pollicis. 

D.  Flexor  brevis  pollicis  (outer 

head). 

E.  Tendon  of  palmaris  longus. 
G.  Adductor  minimi  digiti. 
H.  Adductor  pollicis. 

J.  Abductor  minimi  digiti. 


N.  First  dorsal  interosseous  muscle. 
O.  O.  Two  outer  lumbricales. 

R.  Tendons  of  the  flexor  digitorum 

sublimis. 
S.  Tendon    of    flexor    carpi    ulna- 

ris. 
V.  Flexor  sublimis  tendons  in  the 
palm  of  the  hand. 


K.  Pieces  of  tlie  sheath  of   the  W,  Tendon  of  flexor  profundus  to 


flexor  tendons. 
L.  Part  of  the  palmar  fascia. 


the  ring  finger. 
X.  Anterior  annular  ligament. 


Palmaris  irevis,  A.  This  small  subcutaneous  muscle  is  unattached 
to  bone.  Consisting  of  fleshy  bundles,  more  or  less  separate,  which  are 
attached  to  the  palmar  fascia,  L,  it  is  inserted  into  the  skin  at  the  inner 
border  of  the  hand,  extending  downwards  a  varying  distance  from  the 
pisiform  bone.     Its  insertion  is  marked  by  a  surface  depression. 

"When  the  muscle  contracts  it  elevates  the  skin  on  the  inner  side  of 
the  hand,  and  increases  slightly  the  dejath  of  the  palmar  hollow. 

The  tendon  of  the  palmaris  longus,  E,  enters  the  hand  over  the 
annular  ligament:  from  its  outer  side  an  offset  is  prolonged  to  the  thumb 
muscles,  whilst  the  main  part  ends  in  the  palmar  fascia. 

Tendons  of  the  flexor  sublimis  digitorum,  Y.  Four  in  number,  they 
are  directed  through  the  palm  over  the  deep  flexor;  and  at  the  root  of 
each  finger  one  enters  the  sheath  of  the  digit,  K,  with  a  tendon  of  the 
deep  flexor.  JSTear  the  front  of  the  metacarpal  phalanx  it  is  slit  for  the 
passage  of  the  deep  flexor  tendon,  TV;  and  it  is  inserted  by  two  slips  into 
the  sides  of  the  second  phalanx,  about  half  way  along  the  bone. 

This  muscle  brings  the  middle  phalanges  towards  the  palm,  and  bends 


80  ILLUSTKATIONS    OF    DISSECTIONS. 

thus  the  nearest  phalangeal  joints — the  first  stage  in  the  movement  of 
closing  the  fingers.  As  the  fingers  are  approximated  to  the  palm,  the 
muscle  raises  the  metacarpal  phalanges  by  means  of  the  digital  sheaths 
binding  its  tendons  to  the  bones;  and  it  acts  finally  as  a  flexor  of  the 
wrist-joint. 

Tendons  of  tlie  flexor  profundus  (Plate  ix.),  also  four  in  number, 
cross  the  palm  beneath  the  superficial  flexor,  and  may  be  seen  projecting 
slightly  on  the  sides.  Entering  the  digital  sheaths,  each  is  transmitted 
through  the  accompanying  flexor  sublimis  tendon,  as  is  shown  on  the  ring 
finger,  and  passes  onward  to  be  inserted  by  a  single  piece  into  the  base  of 
the  last  phalanx.  Small  rounded  muscles,  the  lumbricales,  are  attached 
to  these  tendons  in  the  palm  (Fig.  ii.). 

Between  each  tendon  of  the  deep  flexor  and  the  fore  part  of  the  mid- 
dle phalanx  is  a  thin  membranous  band  (opposite  W)  uniting  the  two, 
which  is  called  '^ligamentum  breve;"  and  intervening  in  like  manner 
between  each  piece  of  the  superficial  flexor  and  the  front  of  the  metacar- 
pal phalanx,  is  another  "  ligamentum  breve,"  to  fix  this  tendon  to  the 
underlying  bone. 

The  deep  flexor  draws  forward  the  last  phalanges,  and  bends  the  last 
phalangeal  joints.  Still  continuing  to  shorten,  it  assists  the  superficial 
flexor  in  bending  the  metacarpo-phalangeal  joints  in  the  act  of  shutting 
the  fingers;  and  combined  with  the  same  muscle,  it  will  flex  the  wrist 
when  the  digits  are  closed. 

In  amputating  on  the  living  body  through  the  phalangeal  articula- 
tions, some  difficulty  is  experienced,  when  the  joint  is  opened  at  the 
back,  in  entering  the  knife  between  the  ends  of  the  bones,  owing  to  the 
flexor  tendon  drawing  the  distal  against  the  nearer  phalanx;  and  this 
difficulty  is  increased  in  the  case  of  the  last  joint,  in  consequence  of  the 
smallness  of  the  part  to  be  held  preventing  sufficient  force  being  employed 
to  overcome  the  tendon.  When  the  joint  is  opened  at  the  front  the 
impeding  tendon  has  been  previously  cut,  and  the  operation  can  be  exe- 
cuted without  hindrance  to  the  passage  of  the  knife. 

Sheath  of  the  flexor  tendons,  K.  In  each  finger  this  reaches  from  the 
palm  of  the  hand  to  the  last  phalanx.  It  is  constructed  on  the  one  side 
by  the  bones;  and  on  the  other  by  fibrous  bands,  which  are  thinnest 
opposite  the  joints:  these  thinner  pieces  have  been  removed  in  the  dis- 
section. 

A  synovial  membrane  lines  each  sheath,  projecting  into  the  palm  of 


SUPERFICIAL    ARTERIES   OF   THE   HAND. 


81 


the  hand,  where  it  is  closed;  and  long  tapering  folds  (vincula  vasculosa) 
are  continued  from  it  to  the  tendons:  one  of  these,  connected  with  the 
deep  flexor,  is  shown  in  the  opened  sheath  of  the  ring  finger.  In  the 
thumb  and  the  little  finger  the  synovial  membrane  of  the  sheath  is  con- 
tinued upwards  into  a  large  synovial  sac  which  surrounds  the  tendons  of 
both  flexors  beneath  the  annular  ligament. 


SUPERFICIAL  ARTERIES  OF  THE  HAND. 

The  arrangement  of  the  superficial  palmar  arch  and  its  offsets,  which 
is  described  as  the  usual  one,  is  figured  here,  but  many  hands  were  exam- 
ined before  this  condition  was  found.  The  arteries  to  the  thumb  and 
the  radial  side  of  the  fore  finger  will  be  described  in  the  exj)lanation 
of  Fig.  ii. 


a.  Ulnar  artery  in  the  forearm. 

b.  Radial  artery  in  the  forearm. 

c.  Superficial  palmar  arch. 

d.  Superficial  volar  branch. 

/.  Four    digital    branches    of    the 
superficial  palmar  arch. 


g.  Communicating  artery  from  the 
palmar  arch  to  the  radial  branch 
of  the  index  finger. 

h.  Communicating  branch  to  the 
deep  arch  from  the  digital  ar- 
tery of  the  little  finger. 


The  ulnar  artery,  a,  enters  the  hand  over  the  annular  ligament,  and 
curving  towards  the  ball  of  the  thumb  forms  the  superficial  palmar  arch: 
it  supplies  branches  to  the  greater  number  of  the  digits. 

The  superficial  palmar  arch — the  continuation  of  the  ulnar  artery — 
lies  across  the  hollow  of  the  hand,  between  the  lower  border  of  the  annu- 
lar ligament  and  the  ball  of  the  thumb.  With  its  convexity  towards  the 
fingers,  it  reaches  nearly  as  far  forwards  as  a  line,  across  the  palm,  from 
the  middle  of  the  fold  between  the  thumb  and  the  forefinger.  Diminish- 
ing in  size,  it  ends  externally  by  joining  branches  of  the  radial,  viz.,  the 
superficial  volar  branch,  d,  pretty  constantly,  and  the  branch  to  the 
radial  side  of  the  forefinger  (Fig.  ii.,  d)  occasionally,  by  means  of  the 
small  communicating  branch,  g. 

At  its  inner  end  the  arch  is  covered  by  the  palmaris  brevis  muscle,  A, 
and  thence  to  the  ball  of  the  thumb,  by  the  integuments  and  the  palmar 
fascia;  it  rests  on  the  tendons  of  the  flexors  of  the  digits,  and  on  the 
ulnar  and  median  nerves.     Companion  veins  lie  on  the  sides  of  the  artery. 


82  ILLUSTRATIONS    OF   DISSECTIONS. 

From  the  concavity  of  the  arch  spring  small  unnamed  offsets;  and  from 
the  convexity  digital  arteries  proceed. 

The  digital  arteries,  four  in  number,  and  marked  each  with  the  letter 
/,  supply  three  digits  and  a  half.  In  their  course  to  the  digits  the  three 
outer  lie  over  interosseous  spaces,  whilst  the  other  is  placed  along  the 
inner  part  of  the  palm  ;  and  at  the  cleft  of  the  fingers  they  divide,  except 
the  most  internal,  into  two  for  the  contiguous  sides  of  the  digits.  Cours- 
ing along  the  fingers  they  are  united  by  a  loop  behind  each  phalangeal 
joint ;  and  at  the  end  of  the  finger  they  terminate  in  a  loop  which  gives 
offsets  to  the  tip,  as  is  seen  on  the  fourth  digit. 

The  following  communications  take  place  between  the  digital  arteries 
of  the  ulnar  and  the  branches  of  the  radial.  At  the  inner  side  of  the 
palm  the  branch  li,  which  springs  from  the  artery  to  the  inner  side  of 
the  little  finger,  joins  either  the  deep  arch  or  an  interosseous  branch  ;  at 
the  roots  of  the  fingers  the  digital  arteries  anastomose  with  the  inter- 
osseous branches  of  the  deep  arch  ;  and  at  the  tip  of  the  forefinger  the 
digital  artery  on  the  ulnar  side  inosculates  with  the  arteria  radialis 
indicis. 

In  the  hand  the  large  digital  vessels  and  nerves  lie  over  the  intervals 
between  the  metacarpal  bones  ;  and  in  the  fingers  they  occupy  the  sides. 
Incisions  into  the  palm  of  the  hand  can  be  made  therefore  with  least 
injury  over  the  line  of  the  metacarpal  bones  ;  and  a  cut  into  a  finger, 
along  its  centre. 

Wounds  of  arteries  in  the  palm  of  the  hand  are  followed  generally 
by  copious  bleeding,  in  consequence  of  the  numerous  communications 
between  the  chief  vessels.  In  an  injury  of  the  superficial  palmar  arch,  at 
c,  for  instance,  blood  will  be  furnished  by  the  ulnar  trunk,  a.  And 
though  this  source  might  be  cut  off  by  a  ligature,  the  blood  could  be 
supplied  by  the  radial  artery  to  the  other  end  of  the  arch,  through  the 
anastomosing  branches,  d  and  g ;  or  through  the  anastomoses  above 
described  of  the  digital  with  the  interosseous  arteries,  and  with  the  arteria 
radialis  indicis.  In  such  an  arrangement  of  the  vessels  as  that  delineated 
in  the  Figure,  the  bleeding  from  the  wound  might  be  commanded  by 
placing  a  ligature  on  each  side  of  the  orifice  in  the  artery  ;  or,  as  is  more 
commonly  done,  by  stopping  the  currents  in  the  radial  and  ulnar  trunks 
by  pressure  above  the  wrist,  and  by  applying  a  graduated  compress  to 
the  seat  of  injury.  If,  when  the  orifice  of  the  artery  has  not  been 
secured  by  a  thread,  pressure  has  been  found  ineffectual  in  stopping  the 


SUPERFICIAL    ARTERIES    OF    THE    HAND.  83 

bleeding,  ligature  of  the  ulnar  artery,  or  of  this  and  the  radial,  would 
have  to  be  performed  in  addition  to  a  compress  to  the  wound. 

But  there  is  an  occasional  condition  of  the  vessels,  which  renders  the 
arrest  of  the  hemorrhage  difficult  unless  the  artery  is  tied  in  the  wound. 
For  instance,  a  third  artery,  sometimes  as  large  as  either  the  radial  or 
the  ulnar,  may  join  the  middle  or  the  outer  part  of  the  superficial  palmar 
arch,  so  as  to  bring  blood  freely  to  the  wound.  And  as  this  vessel 
(usually  an  offset  of  the  anterior  interosseous,  but  sometimes  of  the 
brachial  or  the  radial  * )  courses  with  tlie  median  nerve  beneath  the 
annular  ligament,  and  generally  beneath  the  muscles,  pressure  would  not 
be  productive  of  much  benefit  in  stopping  the  current  in  it,  and  ligature 
of  it  would  be  scarcely  practicable.  Eecurring  bleeding  with  the  exist- 
ence of  this  state  of  the  vessels  would  be  quite  uncontrollable  by  means 
which  would  arrest  it  when  the  ordinary  arrangement  existed. 

As  the  state  of  the  palmar  wound  is  sometimes  unfavorable  to  any 
attempt  to  place  a  ligature  on  the  vessel  there,  and  as  surgeons  have  a 
reasonable  disinclination  to  enlarge  wounds  of  the  palm  to  search  for  the 
bleeding  orifice,  ligature  of  the  brachial  trunk  has  been  practised  when 
the  bleeding  resists  the  usual  means  of  stopping  it.  The  following  case, 
illustrative  of  the  inefficacy  of  securing  the  main  trunk  of  the  limb  at  a 
distance  from  the  wound  when  a  large  branch  joins  the  arch  directly,  as 
in  the  condition  stated  above,  is  instructive. 

*'A  young  man  wounded  his  palmar  arch  :  secondary  haemorrhage 
took  place  several  times  ;  the  radial  and  ulnar  were  tied,  but  the  bleed- 
ing returned;  an  artery  of  some  size,  a  'vas  aberrans,' was  discovered 
beating  in  the  middle  of  the  forearm,  close  under  the  skin ;  a  ligature 
was  put  on  the  brachial  in  the  middle  of  the  arm,  with  the  hope  of  get- 
ting above  the  origin  of  the  abnormal  branch ;  it  (the  unusual  branch) 
continued  however  to  pulsate  after  the  ligature  was  tightened ;  tlie  vas 
aberrans  itself  was  therefore  tied  at  once,  close  below  the  elbow,  but  not- 
withstanding all  these  precautions,  haemorrhage  occurred  on  the  follow- 
ing day  as  violent  as  ever ;  the  Avound  (in  the  palm)  was  a  second  time 
enlarged,  and  fortunately  the  blood  burst  forth  at  the  time  of  operation 
and  the  wounded  artery  was  easily  tied  :  the  patient  recovered  rapidly,  "f 

*  Examples  of  these  conditions  of  the  arteries,  collected  chiefly  by  Mr.  Quain, 
are  contained  in  the  museum  of  University  College,  London. 

f  This  case  is  reported  by  Mr.  Cadge,  in  the  part  of  Morton's  Surgical  Anatomy 


84 


ILLUSTRATIONS    OF    DISSECTIONS. 


The  result  of  ligature  of  the  brachial  in  the  above-cited  case  teaches, 
that  tying  the  vessel  in  the  wound  of  tlie  palm,  if  such  a  step  is  possible, 
is  to  be  preferred  to  a  distant  operation  on  the  main  artery  of  the  limb, 
in  those  instances  in  which  the  surgeon  suspects  that  a  large  unusual 
median  artery  joins  the  superficial  palmar  arch. 


SUPERFICIAL  KERVES  OF  THE   HAND. 

The  median  and  ulnar  nerves  divide  in  the  palm  of  the  hand  into  large 
branches,  which  end  on  the  digits  as  the  nerves  of  touch.  They  give 
branches  to  the  superficial  muscles;  and  the  ulnar  nerve  supplies  also  the 
deep  muscles  by  means  of  a  special  offset. 


1.  Trunk  of  the  median  nerve. 

2.  First  digital  branch. 

3.  Second  digital  branch. 

4.  Third  digital  branch. 

5.  Fourth  digital  branch. 

6.  Fifth  digital  branch. 


7.  Communicating  branch   from  the 

median  to  the  ulnar. 

8.  Outer  digital  branch  of  the  ulnar. 

9.  Inner  digital  branch  of  the  ulnar. 
10.  Ti-unk  of  the  ulnar  nerve. 


T\\e  median  nerve,  1,  is  the  larger  of  the  two  trunks  distributed  in  the 
hand.  Issuing  from  beneath  the  annular  ligament,  it  is  consumed  chiefly 
in  five  digital  branches  which  supply  both  sides  of  each  of  the  three 
outer  digits,  and  the  outer  side  or  half  of  the  ring  finger.  Comparatively 
few  branches  are  furnished  to  muscles. 

The  dir/ital  h^ancJies  are  continued  through  the  .palm  of  the  hand,  and 
along  the  sides  of  the  digits  to  the  extremity,  where  they  end  in  a  tuft  of 
offsets  for  the  supply  of  the  ball  and  nail-pulp  of  the  finger.  To  the 
skin  of  the  palm  and  the  surface  of  the  digits  they  give  many  branches. 

Two  of  them  supply  lumbrical  muscles;  thus  the  third  nerve,  4,  gives 
a  branch  to  the  most  external  lumbricalis;  and  the  fourth  nerve,  5,  to  the 
next  following  muscle. 

Muscular  hranclies.     Part  of  the  fleshy  ball  of  the  thumb  is  supplied 


which  was  completed  by  him  (London,  1850,  p.  371).  The  arteiy  named  "vas 
aberrans,"  does  not  correspond  with  the  arteries  commonly  so  called  ;  and  it  was 
probably  the  "median  artery,"  which  sometimes  arises  from  the  lower  end  of 
the  brachial,  and  joins  the  palmar  arch,  as  Plate  45  of  Mr.  Quain's  Work  on  the 
Surgical  Anatomy  of  the  Arteries  illustrates. 


SPECIAL    MUSCLES    OF    THE    HAND.  85 

by  the  branch,  8;  this  is  distributed  to  tlie  muscles  outside  tliehjng  flexor 
tendon,  viz.,  to  tlie  abductor  pollicis,  B,  opponens  pollicis,  C,  and  the 
outer  head  of  the  short  flexor,  D. 

If  the  median  nerve  was  cut  througli  close  to  the  annular  ligament, 
sensibility  Avould  be  destroyed  m  the  palmar  surface  of  the  hand  and 
fingers  outside  a  line  drawn  from  the  middle  of  the  ring  finger  to  the  wrist; 
and  it  would  be  diminished  at  the  dorsal  aspect  of  the  three  outer  digits 
beyond  the  matacarpo-phalangeal  joints,  Avhere  offsets  from  the  digital 
nerves  ramify. 

The  muscles  of  the  thumb  before  referred  to  as  supplied  by  the  median, 
and  marked  B,  C,  and  D,  together  with  the  outer  two  lumbricales,  would 
be  paralyzed. 

The  ulnar  nerve,  10,  divides  on  the  annular  ligaments  into  a  super- 
ficial or  digital,  and  a  deep  or  muscular  part. 

Erom  the  superficial  part  two  digital  branches,  8  and  9,  are  furnished 
to  the  little  finger  (both  sides),  and  to  half  the  ring  finger;  these  have  a 
similar  distribution  to  the  digital  nerves  of  the  median. 

The  branch  marked  9  sends  offsets  to  the  palmaris  brevis  muscle,  and 
the  integuments  of  the  inner  part  of  the  hand;  and  the  external  of  the 
two,  8,  receives  a  connecting  branch,  7,  from  the  median  nerve. 

Insensibility  of  the  palmar  surface  of  the  hand  and  fingers,  inside  a 
line  from  the  ring-finger  to  the  wrist,  follows  incision  of  the  trunk  of  the 
ulnar  nerve;  and  the  power  of  feeling  Avould  be  lost  at  the  same  time  on 
the  back  of  the  two  inner  fingers  which  are  supplied  by  the  same  nerve. 
Besides  the  joaralysis  of  the  deep  muscles  attending  injury  of  the  nerve, 
which  will  be  noticed  in  the  description  of  Fig.  ii.,  the  small  palmaris 
muscle,  A,  will  lose  its  power  of  contracting. 

Figure  II. 

Most  of  the  special  muscles  of  the  hand,  and  the  deep  palmar  arch, 
with  its  companion  nerve,  are  represented  in  the  right-hand  Figure  of 
the  Plate. 

This  dissection  follows  the  preceding;  and  to  carry  it  out,  the  super- 
ficial palmar  arch  and  the  ulnar  and  median  nerves  are  to  be  cut  through 
at  the  annular  ligament,  and  are  to  be  taken  away:  then  the  sujoerficial 
and  deep  flexor  tendons  having  been  cut  at  the  same  spot,  are  to  be 
thrown  forwards  to  the  digits — the  lumbrical  muscles  attached  to  the 
deep  tendons  being  cleaned  as  the  superficial  tendons  are  raised. 


86 


ILLUSTRATIONS    OF   DISSECTIONS. 


SPECIAL  MUSCLES  OF  THE  HAND. 

All  the  muscles  which  have  both  origin  and  insertion  in  the  hand  will 
be  now  described,  with  the  exception  of  the  pulmaris  brevis.  They  con- 
sist of  three  sets:  a  thumb  group,  a  little-finger  group,  and  a  central 
group  for  the  other  digits. 


B.  Abductor  pollicis. 

C.  Opponens  pollicis. 

D.  Outer  head  of  flexor  brevis  polli- 

cis. 
F.  Inner  head  of  flexor  brevis. 
H.  Adductor  pollicis. 
J.  Abductor  minimi  digiti. 
K.  Flexor  brevis  minimi  digiti, 
L.  Adductor  minimi  digiti. 


M.  Tendon  of  the  flexor  longus  polli- 
cis. 

N.  First  dorsal  interosseous. 

O.  Lumbricales  muscles. 

P.  Interossei  of  the  hand. 

R.  Tendon  of  flexor  digitorum  sub- 
limis. 

S.  Tendon  of  flexor  carpi  ulnaris. 

T.  Tendon  of  flexor  carpi  radialis. 

V.  Tendons  of  flexor  profundus. 


The  tliumh  muscles,  four  in  number,  consist  of  an  abductor,  an  ad- 
ductor, and  a  flexor,  with  a  special  muscle  to  oppose  the  thumb  to  the 
other  digits. 

Abductor  pollicis,  B.  This  is  the  most  superficial  muscle.  It  arises 
behind  from  the  annular  ligament,  and  the  ridge  of  the  trapezium  bone; 
and  is  inserted  by  a  tendon  into  the  outside  of  the  base  of  the  first 
phalanx. 

The  muscle  draws  away  the  thumb  from  the  index  finger. 

Adductor p)ollicis,  H.  The  origin  of  the  muscle,  which  is  not  always 
separate  from  the  inner  head  of  the  flexor  brevis,  is  fixed  to  the  ridge  on 
the  palmar  surface  of  the  metacarpal  bone  of  the  middle  finger;  and  the 
muscle  is  inserted  with  the  inner  head,  F,  of  the  short  flexor  into  the 
inner  side  of  the  base  of  the  first  phalanx. 

By  its  action  the  thumb  is  placed  on  the  palm  and  the  fore  finger,  so 
as  to  deepen  externally  the  hollow  of  the  hand. 

Opponens  pollicis,  C.  The  muscle  is  partly  covered  by  the  abductor, 
and  arises,  like  it,  from  the  annular  ligament  and  the  prominence  of  the 
trapezium  bone:  it  is  inserted  into  the  metacarpal  bone  of  the  thumb 
along  the  outer  edge. 


SPECIAL    MUSCLES    OF    THE    HAND.  87 

This  muscle  can  abduct  the  metacarpal  bone,  and  can  then  so  move 
it  as  to  allow  the  ball  of  the  thumb  to  bo  turned  opposite  the  ball  of  each 
digit,  as  in  the  act  of  picking  up  a  pea  Avith  the  thumb  and  each  finger. 

The  flexor  Irevis  poUtcis  is  divided  into  two  pieces  or  heads,  D  and 
F,  at  its  insertion  into  the  thumb.  Single  at  its  hinder  attachment  or 
origin,  it  is  fixed  to  the  annular  ligament  near  the  lower  edge,  to  two 
carjDal  bones  (os  trapezoides  and  os  magnum),  and  to  the  bases  of  the  two 
metacarpal  bones  answering  to  the  two  carpals.  The  fibres,  collected 
into  two  bundles  which  are  separated  by  the  tendon,  M,  of  the  long  flexor, 
are  inserted  into  the  sesamoid  bones,  and  the  base  of  the  first  phalanx — 
the  outer  head,  D,  joining  the  abductor,  and  the  inner  head,  F,  blending 
with  the  adductor  pollicis. 

This  muscle  bends  the  metacarpo-phalangeal  joint  of  the  thumb;  it 
draws  inwards  also  the  thumb  over  the  palm  and  approaches  it  to  the 
other  digits. 

Little-finger  muscles.  The  group  of  muscles  connected  with  the  little 
finger  contains  three,  viz.,  an  abductor,  an  adductor,  and  a  short  flexor, 
as  in  the  thumb;  but  the  flexor  is  sometimes  absent. 

Abductor  minimi  digiti,  J,  arises  behind  from  the  pisiform  bone  ;  and 
is  inserted  into  the  base  of  the  first  jjhalanx  on  the  inside,  sending  an  off- 
set to  join  the  extensor  tendon.* 

It  draws  the  little  from  the  ring  finger,  and  assists  in  bending  the 
metacarpo-phalangeal  joint. 

Adductor  minimi  digiti,  vel  opponens,  L,  arises  posteriorly  from  the 
annular  ligament,  and  the  hook  of  the  unciform  bone;  and  it  is  inserted 
into  the  inner  side  of  the  fifth  metacarpal  bone. 

The  fibres  shortening  as  they  contract,  draw  forwards  the  metacarpal 
bone,  and  deepen  the  hollow  of  the  palm. 

Flexor  hrevis  minimi  digiti,  K,  takes  origin  from  the  annular  ligament 
and  the  unciform  jDrocess,  superficial  to  the  preceding  muscle;  it  is  in- 
serted with  the  abductor  into  the  base  of  the  first  phalanx. 

By  its  position  in  the  hand  this  muscle  is  enabled  to  act  as  a  flexor  of 
the  metacarpo-phalangeal  joint. 

In  the  central  group  of  the  hand  are  included  superficial  and  deep 
muscles:  the  former,  or  the  lumbricales,  are  attached  to  the  deep  flexor 

*  Lehre  von  den  Muskeln,  etc.  Von  Friedrich  Wilhehn  Theile.  Leipzig,  1841, 
p.  283. 


88  ILLUSTRATIONS    OF    DISSECTIONS. 

tendons ;  and  the  latter,  the  interossei,  lie  between  the  metacarpal 
bones. 

The  lumhrical  muscles,  four  in  number,  and  marked  by  the  letter  0, 
arise  from  the  tendons  of  the  flexor  digitorum  profundus,  near  the  wrist. 
Placed  on  the  radial  side  of  the  flexor  tendons,  each  joins,  opposite  the 
metacarpo-phalangeal  joint,  the  extensor  tendon  on  the  back  of  the  first 
phalanx.  The  two  external  muscles  arise  each  from  a  single  tendon,  and 
the  two  internal  from  two  tendons  for  each. 

They  flex  the  metacarpo-phalangeal  joints  by  bringing  forwards  the 
first  phalanges,  and  assist  the  special  flexors  in  closing  the  fingers. 

The  interossei  muscles  occupy  the  inter-metacarpal  spaces — two  being 
present  in  each  space  except  the  first,  in  which  there  is  only  one:  they  are 
divided  into  two  sets,  palmar  and  dorsal. 

The  dorsal  set,  four  in  number,  are  shown  in  Plate  xi.  Each  arises 
from  the  tvv^o  bones  bounding  the  metacarpal  space,  and  is  inserted  into 
the  base  of  the  metacarpal  j)halanx,  chiefly  into  the  bone,  though  it  joins 
also  the  extensor  tendon  by  a  fibrous  jirocess.  The  first  or  most  ex- 
ternal, which  is  sometimes  called  abductor  indicis,  is  the  largest:  it  is 
marked  by  N. 

These  muscles  act  as  abductors  of  the  fore  and  ring  fingers  from  the 
middle  one;  and  they  can  move  the  last-mentioned  digit  to  each  side  of 
a  line  passing  lengthwise  through  it.  The  first  may  adduct  the  meta- 
carpal bone  of  the  thumb  to  that  of  the  index  finger. 

H\iQ  palmar  set,  only  three  in  number,  lie  in  the  three  inner  spaces; 
and  the  middle  finger  does  not  receive  any  of  this  set.  Arising  from  the 
metacarpal  bone  of  the  finger  to  which  each  belongs,  they  are  inserted, 
like  the  dorsal,  into  the  nearest  phalanx  of  the  fingers;  each  has  but  a 
slight  attachment  to  the  bone,  blending  most  with  the  extensor  tendon.* 

When  acting  they  bring  together  the  separated  fingers,  and  will  draw 
the  fingers,  into  which  they  are  inserted,  viz.,  the  fore,  ring,  and  little, 
towards  the  middle  digit. 

DEEP  ARTERIES  OF  THE   HAND. 

The  radial  artery  ends  in  the  palm  of  the  hand  by  forming  an  arch; 
and  it  furnishes  arteries  to  the  digit  and  a  half  left  unsupplied  by  the 

*  This  difference  in  the  insertion  of  the  dorsal  and  palmar  sets,  is  stated  by 
Theile  in  the  work  on  the  muscles  before  quoted,  p.  286. 


DEEP    ARTERIES    OF    THE    HAND. 


89 


ulnar  trunk.     It  enters  likewise  into  numerus  communications  with  ofl'- 
sets  of  tlie  ulnar  artery. 


a.  Deep  palmar  arch. 

b.  Profunda  branch   of    the    uhiar 

artery. 

c.  Large  artery  of  the  thumb. 

d.  Digital  artery  to  the  radial  side 

of  the  fore  fins;er. 


e.  Communicating  branch  of  the 
deep  arch  from  the  digital 
artery  to  the  little  finger. 

/.  /.  Two  inner  interosseous  arteries. 

It,  h.  Offsets  to  lumbrical  muscles. 


Radial  artery.  Passing  into  the  hand  through  the  first  interosseous 
space,  it  furnishes  digital  arteries  to  the  thumb  and  the  fore  finger,  and 
ends  in  the  deep  palmar  arch. 

The  digital  artery  of  the  tliuiiib,  c  (art.  magna  pollicis),  courses  along 
the  metacarpal  bone,  and  divides  into  two  branches  near  the  joint 
between  that  bone  and  the  phalanx:  these  supply  the  sides  of  the  thumb, 
and  join  at  the  tip  in  the  usual  way. 

The  digital  artery  of  the  index  finger,  d  (art.  radialis  indicis),  lies 
along  the  second  metacarpal  bone;  and  issuing  from  beneath  the  adduc- 
tor pollicis,  H,  rtins  on  the  radial  border  of  its  digit  to  the  extremity, 
Avhere  it  anastomoses  with  the  digital  artery  from  the  suj^erficial  palmar 
arch.  Sometimes  it  joins  the  superficial  palmar  arch  through  a  branch, 
g,  Fig.  I. 

The  deep  palmar  arch,  a,  is  the  curve  formed  by  the  end  of  the  radial 
arter3^  It  reaches  from  the  first  to  the  fourth  interosseous  space,  but 
placed  near  the  carpus,  and  is  rather  convex  forwards,  like  the  superficial 
arch.  At  the  inner  end  it  communicates  with  the  jirofunda  branch,  h, 
of  the  ulnar;  and  with  the  branch,  e,  belonging  to  the  digital  artery  of 
the  inner  side  of  the  little  finger.  The  arch  has  a  deep  position  in  the 
hand; — internally  it  is  covered  by  the  adductor  minimi  digiti,  L;  exter- 
nally by  the  inner  head  of  the  flexor  brevis  pollicis,  F;  and  between  these, 
by  the  flexor  tendons:  it  rests  on  the  three  middle  metacarpal  bones,  and 
their  intervening  muscles. 

Offsets  of  the  arch. — From  the  concavity  small  offsets  are  directed 
back  to  the  carpus.  Three  small  perforating  arteries  pierce  the  three 
inner  dorsal  interosseous  muscles  to  reach  the  back  of  the  hand.  The 
chief  branches  are  described  below : — 

Interosseous  branches,  f,  f. — Only  two  of  these  now  appear,  and  the 
third  lies  beneath  the  adductor  pollicis:  they  extend  to  the  clefts  of  the 


90  ILLUSTRATIONS    OF    DISSECTIONS. 

fingers,  giving  muscular  twigs,  and  end  by  joining  the  digital  arteries  of 
the  superficial  arch. 

Muscular  tranches,  h,  h,  supply  the  two  or  three  inner  lumbrical 
muscles. 

Through  the  communication  of  the  radial  with  the  ulnar  artery  at 
the  inner  side  of  the  hand,  blood  would  find  its  way  directly  into  the 
superficial  palmar  arch,  after  ligature  of  the  ulnar  trunk  above  the  wrist; 
and  by  means  of  the  anastomoses  between  the  branches  of  the  two 
arteries  (p.  82),  the  blood  would  be  conveyed  from  the  superficial  to 
the  deep  arch. 

Wounds  of  the  deep  arch  are  rare,  in  consequence  of  its  deeper  and 
securer  position  in  the  hand;  and  ligature  of  the  vessel  would  be  often- 
times impossible.  Supposing  the  wounded  vessel  cannot  be  reached,  the 
bleeding  would  most  commonly  be  arrested  by  a  graduated  compress  to 
the  wound,  and  by  pressure  on  the  radial  and  ulnar  arteries  in  the  lower 
third  of  the  forearm.  If  those  means  fail  to  stop  the  bursting  forth  of 
the  blood,  ligature  of  the  radial  artery — the  chief  vessel  entering  the 
arch — would  probably  be  effectual  in  commanding  the  ha3morrhage. 
vShould  bleeding  still  occur,  and  possibly  from  large  communicating 
branches  with  the  ulnar  artery,  for  no  large  unusual  artery  joins  the  deep 
arch,  tying  the  ulnar  trunk  might  be  tried.  As  a  last  resource  ligature 
of  the  brachial  artery  remains. 

DEEP  NERVE  OF  THE  PALM. 

The  ulnar  nerve  is  distributed  to  those  muscles  of  the  inner  and  deep 
parts  of  the  palm  of  the  hand,  which  do  not  receive  branches  from  the 
median  nerve. 


1,  1.  Branches     to     the    lumbrical 
muscles. 


2.  Deep  palmar  branch  of  the  ulnar 

nerve. 

3.  Trunk  of  the  ulnar  nerve. 


The  deep  palmar  branch,  2,  of  the  ulnar  nerve,  arising  near  the  wrist, 
passes  deeply  between  the  flexor  brevis  and  abductor  minimi  digiti,  or 
through  the  adductor  muscle,  L,  as  in  the  Figure,  and  accompanies  the 
radial  arch  to  the  first  interosseous  space,  where  it  ends  by  supplying 
the  adductor  pollicis,  H,  and  the  inner  head,  F,  of  the  flexor  brevis 
pollicis. 


PLATE  XI 


'^1 


/ 


■SUPERFICIAL    MUSCLES.  91 

Muscular  offseis  are  furnished  to  the  muscles  of  the  little  finger,  viz., 
adductor,  J,  flexor  brevis,  K,  and  adductor,  L;  to  all  the  seven  inter- 
ossei  muscles;  and  to  the  inner  two  lumbricales. 

All  the  muscles  of  the  hand,  except  two  and  a  half  of  the  thumb  and 
the  two  outer  lumbricales,  receive  branches  from  the  deep  part  of  the 
ulnar  nerve.  Destruction  of  the  trunk  of  the  ulnar  nerve  in  the  arm 
Avould  affect  the  movements  of  the  thumb  and  fingers;  but  notably  those 
of  the  little  and  ring  fingers,  whose  short  or  hand  muscles  depend  solely 
on  the  ulnar  nerve  for  their  contractile  power. 


DESCRIPTION  OF  PLATE  XI. 


The  dissection  of  the  superficial  muscles  and  vessels  on  the  back  of 
the  forearm  and  hand  is  here  illustrated. 

This  view  was  obtained  by  reflecting  the  integuments  from  the  elbow 
to  the  roots  of  the  fingers;  and  by  removing  the  deep  fascia,  with  the 
exception  of  the  posterior  annular  ligament  near  the  wrist.  The  fore 
finger  was  then  denuded  of  its  cutaneous  coverings,  to  trace  the  extensor 
tendon  to  the  end. 

SUPERFICIAL  MUSCLES. 

At  the  back  of  the  forearm  are  located  the  muscles  which  oppose  by 
their  action  the  muscles  in  front ;  and  as  the  anterior  group  consists  of 
flexors  and  pronators,  so  the  posterior  includes  their  antagonists — exten- 
sors and  supinators. 

The  posterior  set  is  divided,  like  the  anterior,  into  superficial  and 
"deep  layers.  In  the  superficial  layer  are  contained  one  supinator,  and 
the  extensors  of  the  wrist  and  digits,  which  are  indicated  below  by  the 
letters  of  reference. 

A  few  of  the  deeper  muscles  appear  near  the  wrist,  but  these  will  be 
described  with  Plate  xii. 


^)2 


ILLUSTRATIONS    OF    DISSECTIONS. 


A.  Biceps  flexor  brachii. 

B.  SuDinator  longus. 

C.  Extensor  carpi  radialis  longior. 

D.  Extensor  carpi  radialis  brevior. 

E.  Extensor  digitorum  communis. 

F.  Extensor  minimi  digiti. 

G.  Extensor  carpi  ulnaris. 
H.  Anconeus. 

J.  Brachialis  anticus. 

K.  Extensor  ossis  metacarpi  pol- 
licis. 

L.  Extensor  primi  internodii  pollicis. 

N.  Extensor  secundi  internodii  pol- 
licis. 


O.  Dorsal  interosseous  muscle. 

P.  Fibrous  bands  joining  the  ex- 
tensor tendons  near  the  knuc- 
kles. 

R.  Expansion  from  the  extensor 
tendon  opposite  the  finger 
joints. 

S.  Splitting  of  the  extensor  tendon. 

T.  Insertion  of  the  extensor  tendon 
into  the  last  phalanx. 

V.  Tendon  of  the  indicator  muscle. 

X.  Posterior  annular  ligament. 
f  Deep  fascia  of  the  arm. 


The  siqnnator  longus,  B  ("bracliio-radialis,"  Soemmer.),  is  the  most 
external  muscle;  it  appears  also  in  the  anterior  yiew  of  the  forearm, 
with  the  description  of  which  (Plate,  viii.)  part  of  its  anatomy  has  been 
given. 

Arising,  as  before  said,  from  the  upper  two  thirds  of  the  condyloid 
ridge  of  the  humerus,  and  from  the  intermuscular  septum,  it  is  inserted 
into  the  radius  close  to  the  root  of  the  styloid  process. 

Narrowed  at  the  origin,  it  is  widened  below  the  elbow  over  the  subja- 
cent muscles  forming  the  prominence  on  the  outer  side  of  the  forearm. 
The  anterior  border  touches  the  brachialis  anticus,  J,  the  biceps,  A,  and 
the  pronator  teres  (Plate  viii.) ;  and  the  posterior  edge  is  in  contact  with 
the  extensor  carpi  radialis  longior,  C,  and  with  the  extensor  carpi  radia- 
lis brevior,*  D.  Near  its  insertion  the  tendon  is  covered  by  the  extensors 
of  the  thumb. 

This  supinator  acts  mostly  as  a  flexor  of  the  elbow  joint.     If  the  hand 


*  This  projection  backwards  of  the  supinator  so  as  to  touch  the  extensor  carpi 
radialis  brevior  is  not  referred  to  by  anatomists  of  authority.  It  is  not  repre- 
sented by  Albinus  in  his  standard  work,  Tabular  Anatomicae  Musculorum  Homi- 
nis.  Lond.,  1747;  nor  in  the  modern  work  of  Bourgery  and  Jacob,  Traite  complet 
de  1' Anatomic  de  I'Homme.  Paris,  1833.  Neither  Theile,  in  his  treatise  on  the 
muscles  in  Soemmerring's  Anatomy  (Lehre  von  den  Muskeln,  etc.  Leipzig,  1841), 
nor  Henle,  in  his  recent  Handbuch  der  Systematischen  Anatomic  des  Menschen; 
Dritte  Abtheilung,  Braunschweig,  1858,  takes  notice  of  the  fact.  Cruveilhier  is 
silent  also  respecting  this  connection  of  the  muscle  in  his  systematic  work,  Traite 
d' Anatomic  descriptive.     Deuxieme  edition.     Paris,  1843. 


SUPERFICIAL    MUSCLES    OF   THE    FOREARM.  93 

is  greatly  pronated,  the  muscle  can  draw  backwards  the  radius  to  a  small 
extent;  and  if  the  hand  is  much  supinated,  tlie  lower  end  of  the  radius 
will  be  moved  somewhat  forwards  as  in  pronation:  in  both  cases  the 
hand  is  brought  into  a  state  midway  between  pronation  and  supination 
(Theile). 

The  extensor  carpi  radialis  longior,  C,  arises  from  the  lower  third  of 
the  outer  condyloid  ridge  of  the  humerus,  and,  below  the  elbow,  from 
the  intermuscular  septum  between  it  and  the  following  extensor.  In  the 
lower  joart  of  the  forearm  its  tendon  passes  through  the  posterior  annular 
ligament  Avith  the  shorter  extensor,  and  is  inserted  into  the  base  of  the 
metacarpal  bone  of  the  index  finger. 

The  muscle  is  superficial  above  and  below;  but  it  is  covered  by  the 
supinator  longus  in  the  upper  j^art  of  the  forearm. 

The  extensor  carpi  radialis  irevior,  D,  takes  origin  from  the  outer 
condyle  of  the  humerus  by  the  common  tendon,*  and  from  the  capsule 
of  the  elbow  joint.  Beyond  the  annular  ligament  the  tendon  is  inserted 
into  the  base  of  the  metacarpal  bone  of  the  second  finger. 

This  extensor  is  superficial  in  great  part,  but  two  muscles  of  the 
thumb,  K  and  L,  rest  on  it  below.  Along  the  outer  edge  lie  the  long 
radial  extensor  of  the  wrist,  and  the  long  supinator. 

Both  radial  extensors  draw  backwards  the  hand,  extending  thus  the 
wrist.  The  longer  muscle  can  assist  the  supinator  m  bending  the  elbow; 
and  the  shorter  one  may  help  in  straightening  the  elbow  after  the  joint 
has  been  bent. 

Extensor  cligitorum  communis,  E.  Attached  above  by  the  common 
origin,  it  ends  below  in  four  tendons:  these  cross  the  back  of  the  hand, 
and  are  inserted  into  the  middle  and  ungual  phalanges  of  the  fingers. 

On  the  hand  the  little  finger  tendon  is  often  united  in  part  with  that 
of  the  ring  finger.  Near  the  knuckles  all  are  joined  by  lateral  bands;  but 
those  of  the  ring-finger  tendon  being  stronger  than  the  rest,  prevent  ex- 
tension of  that  digit  whilst  the  fingers  on  the  sides  (little  and  middle)  are 
bent. 

On  each  finger  the  tendon  forms  a  common  expansion  over  the  first 

*  This  common  tendon  is  fixed  to. the  lower  part  of  the  condyle  and  sends 
downwards  aponeurotic  septa  on  the  under  and  lateral  surfaces  of  three  other 
muscles,  viz.,  the  extensor  digitorum  communis,  extensor  minimi  digiti,  and  ex- 
tensor carpi  ulnaris. 


94:  ILLUSTRATIONS    OF   DISSECTIONS. 

phalanx  with  the  tendons  of  the  lumbricales  and  interossei. *  At  the  front 
of  the  phalanx  this  expansion  divides  into  three,  f  S:  of  these,  the  central 
part  IS  fixed  into  the  second  phalanx  at  the  base:  while  the  two  lateral 
pieces  join,  and  are  inserted  as  one,  T,  into  the  base  of  the  last  phalanx. 
Opposite  each  phalangeal  joint  a  fibrous  expansion  is  continued  from  the 
tendon  to  the  capsule-  on  the  first  joint  this  is  indicated  by  the  letter  E. 

When  straightening  the  fingers  the  muscle  extends  the  joints  from 
root  to  tip,  separating  the  digits  at  the  same  time;  it  acts  secondarily  as 
an  extensor  of  the  wrist.  If  the  elbow  has  been  bent,  it  can  become  an 
extensor,  like  the  other  muscles  which  take  origin  by  the  common  tendon. 

The  extensor  minimi  digiti,  F,  more  or  less  united  with  the  preced- 
ing, is  sometimes  tendinous  in  the  upper  third  of  the  forearm,  as  is 
shown  in  the  Plate.  Arising  by  the  common  attachment,  its  tendon  is 
divided  into  two  beyond  the  annular  ligament,  and  tlie  pieces  blend  on 
the  first  phalanx  with  the  other  tendons. 

The  muscle  extends  the  little  finger,  and  exercises  afterwards  the 
same  action  on  the  wrist  joint. 

Extensor  cmyi  ulnaris,  G-.  With  the  common  origin  above,  the 
muscle  is  fixed  also  by  aponeurosis  to  the  ulna  for  three  inches  below  the 
anconeus,  H.  Passing  through  the  annular  ligament,  it  has  a  tendinous 
insertion  into  the  base  of  the  metacarpal  bone  of  the  little  finger. 

The  hand  is  drawn  backwards  and  to  the  ulnar  side  by  this  muscle. 

Anconeus,  H.  This,  the  smallest  of  the  superficial  muscles,  arises 
from  the  hinder  and  lower  parts  of  the  condyle  of  the  humerus,  and 
chiefly  by  a  separate  tendon.  The  fibres  give  rise  to  a  belly  of  a  triangu- 
ilar  shape  as  they  are  directed  downwards  and  inwards  to  their  insertion 
into  the  upper  third  of  the  ulna,  on  the  posterior  surface.  Some  of  the 
upper  fleshy  fibres  seem  continuous  with  the  fibres  of  the  triceps. 

Inserted  into  the  ulna  it  will  draw  backwards  this  bone — the  humerus 
being  fixed — and  will  extend  the  elbow-joint  in  conjunction  with  the 
triceps. 

Extensors  of  the  thumb.     Three  muscles,  extending  the  thumb,  issue 


*  On  the  back  of  the  fore  and  ring-fingers  tlie  special  extensors  of  tliose  digits 
blend  with  the  common  expansion. 

fin  the  natural  state  a  thin  membrane  connects  the  pieces  of  the  tendon,  but 
this  was  removed  in  the  dissection  to  render  more  evident  the  arrangement  above 
described. 


SUPERFICIAL    MUSCLES    OF   THE    FOREARM.  95 

between  the  common  extensor  of  the  fingers,  E,  and  the  radial  extensors 
of  the  wrist,  C  and  D.  Two,  viz.,  the  extensor  of  the  metacari^al  bone, 
K,  and  that  of  the  first  phahxnx,  L,  lie  close  together  on  the  outer  border 
of  the  forearm:  and  the  third,  the  extensor  of  the  last  phalanx,  N,  is 
placed  below  the  others,  and  is  separated  from  them  by  an  interval.  The 
anatomy  of  these  muscles  will  be  found  in  the  description  of  Plate  xii. 

Indicator  muscle,  V.  Only  below  tlie  annular  ligament  is  the  tendon 
of  this  muscle  visible;  and  it  blends  with  the  common  expansion  on  the 
first  phalanx  of  the  fore  finger. 

The  posterior  annular  ligament,  X,  confines  the  tendons  of  the  mus- 
cles to  the  wrist,  so  as  to  make  the  extensors  of  the  digitis  carry  back- 
wards the  hand  after  the  digits  have  been  straightened.  Formed  mostly 
of  transverse  fibres,  but  continuous  above  and  below  with  the  special 
fascia  of  the  limb,  it  is  fixed  externally  into  the  radius  and  internally, 
where  it  reaches  lower  down,  into  two  bones  of  the  carpus — cuneiform 
and  pisiform. 

As  the  tendons  pass  beneath  this  band  they  are  lodged  in  separate 
channels.  There  are  six  spaces,  in  which  the  tendons  are  arranged  in 
the  following  order: — The  most  internal  compartment  contains  the  exten- 
sor carpi  ulnaris,  G;  and  the  one  that  follows  on  the  outer  side  is  occupied 
by  the  extensor  minimi  digiti,  F.  The  next  space  receives  the  common 
extensor  of  the  fingers,  E,  and  the  special  extensor  of  the  fore  finger,  V; 
and  then  comes  a  narrow  sheath  for  the  extensor  secundi  internodii  pol- 
licis,  N.  Still  to  the  radial  side  is  a  large  space  lodging  the  two  radial 
extensors  of  the  wrist,  C  and  D;  and  most  external  of  all  is  the  tube 
through  which  pass  the  extensor  ossis  metacarpi  pollicis,  K,  and  extensor 
primi  internodii  pollicis,  L.  Each  sheath  in  the  ligament  is  provided 
with  a  synovial  membrane. 

All  the  tendons,  with  one  exception,  lie  in  grooves  in  the  subjacent 
bones,  and  to  the  edges  of  the  grooves  j)rocesses  of  the  fibrous  tissue  are 
attached.  The  tendon  not  resting  on  the  bone  is  that  of  the  extensor 
minimi  digiti,  F,  which  lies  between  the  radius  and  ulna.  On  the  radial 
side  of  that  extensor  the  tendons  groove  the  radius  in  the  order  stated, 
and  on  the  ulnar  side,  one  muscle  (ext.  carpi  ulnaris)  is  lodged  in  a 
hollow  on  the  ulna. 

The  dorsal  interosseous  muscle,  0,  arising  from  the  metacarpal  bones 
bounding  each  space,  are  pierced  behind  by  vessels — the  external  one  by 
the  radial  trunk,  and  the  others,  by  the  perforating  branches  from  the 


96 


ILLUSTRATIONS    OF   DISSECTIONS. 


deep  palmar  arch.     The  attachments  and  the  action  of  these  muscles  are 
described  with  Plate  X. 


ARTERIES   OF  THE   BACK  OF  THE  HAND. 

About  the  wrist,  and  on  the  back  of  tlie  hand,  the  arteries  are  derived 
from  the  radial  and  interosseous  vessels,  and  from  the  deep  palmar  arch. 
Above  the  wrist  only  superficial  branches  of  the  interosseous  vessels 
appear. 


a.  Radial  artery. 

6.  Posterior  carpal  branch. 

e.  Metacarpal  branch. 

d.  Dorsal  branch  of  the  thumb  and 
the  index  finger. 

/.  Dorsal  interosseous  arteries. 

g.  Branch  of  the  posterior  interos- 
seous artery. 


h.  Posterior   part   of  the   anterior 
interosseous  artery, 

k.  Offset  of  the  recurrent  interos- 
seous artery. 
Iff  Cutaneous  offsets  of  the  poste- 
rior interosseous  artery. 


The  radial  artery,  a,  corresponding  with  the  dorsal  artery  of  the  foot 
in  the  lower  limb,  Avinds  over  the  carpal  bones  and  enters  the  hand 
througli  the  first  interosseous  space.  Its  coiinections  are  the  follow- 
ing:— 

In  addition  to  the  common  investments  of  the  limb,  with  superficial 
veins  and  nerves,  the  three  extensors  of  the  thumb  are  directed  over  it; 
— two,  viz.,  extensor  of  the  metacarpal  bone,  K,  and  of  the  first  phalanx, 
L,.lie  close  together,  and  in  a  line  with  the  styloid  process  of  the  radius; 
and  the  other,  the  extensor  of  the  second  phalanx,  N,  crosses  close  to  the 
spot  where  it  enters  the  palm  of  the  hand.  Beneath  the  artery  are  the 
carpus  and  the  external  lateral  ligament  of  the  wrist-joint. 

Small  veins,  and  ramifications  of  the  external  cutaneous  nerve,  ac- 
acompany  the  artery. 

Its  branches  are  inconsiderable  in  size,  but  numerous,  and  are  dis- 
tributed to  the  back  of  the  hand  and  some  digits. 

The  place  of  the  radial  artery  can  be  easily  ascertained  through  the 
skin,  if  the  tendons  crossing  it  are  made  prominent  by  extension  of  the 
thumb;  and  as  the  vessel  is  closer  to  the  extensor  of  the  second  phalanx 
than  to  the  others,  this  tendon  should  be  taken  as  the  guide  to  it. 

Slight  wounds  on  the  back  of  the  wrist  would  be  likely  to  open  the 


ARTERIKS    OF    THE    BACK    OF   THE    HAND.  97 

artery;  and  when  the  radial  lies  over  the  tendons  instead  of  under  them, 
it  is  still  more  superficial,  and  is  more  exposed  to  accident. 

In  disarticulation  of  the  metacarpal  bone  of  the  thumb,  the  artery  lies 
close  to  the  joint,  and  will  be  cut  unless  the  knife  is  kept  near  the  bone. 

Branches  of  the  artery  supply  the  carpus,  the  metacarpus,  and  the 
digits. 

The  posterior  carpal  branch,  h,  forms  an  arch  behind  the  wrist  with 
a  corresponding  branch  of  the  ulnar  artery,  and  communicated  with  the 
posterior  interosseous,  g:  from  this  carpal  arch  interosseous  arteries  are 
sometimes  given  to  the  inner  two  metacarpal  spaces. 

The  metacarpal  branch,  c,  arising  here  in  common  with  the  ]3receding, 
runs  to  the  second  interosseous  space,  and  ends  at  the  front  of  the  space 
in  two  branches  for  the  contiguous  sides  of  the  fore  and  middle  digits  on 
the  dorsal  surface.  Behind  it  receives  a  perforating  branch  from  the 
deep  palmar  arch,  and  in  front  it  communicates  with  the  digital  arteries. 

Dorsal  interosseous  arteries,  f,  f,  lie  over  the  inner  two  interosseous 
muscles,  and  are  derived  from  the  dorsal  carpal  arch;  or  they  may  come 
from  the  perforating  arteries  of  the  deep  palmar  arch,  as  in  the  dissection 
from  which  the  Drawing  was  made.  At  the  cleft  of  the  fingers  they  give 
offsets  to  the  sides  of  the  digits,  and  anastomose  with  the  digital  arteries; 
and  if  they  spring  from  the  dorsal  carpal  arch,  they  receive,  behind,  the 
perforating  arteries  from  the  deejD  palmar  arch. 

Dorsal  branches  of  the  thumb  and  fore  finger. — Two  small  branches 
belong  to  the  thumb,  and  these  run  along  the  metacarpal  bone — one  on 
each  side,  to  the  last  phalanx:  the  inner  one  of  these  is  marked  d;  and 
the  outer  one  springs  from  the  radial  trunk,  abont  half  an  inch  higher 
up.  There  is  one  branch  for  the  fore  finger,  which  is  continued  on  the 
radial  side  of  that  digit,  and  supplies  the  integuments;  in  this  body  it  is 
conjoined  with  the  inner  artery  to  the  dorsum  of  the  thumb. 

Both  the  posterior  interosseous  artery,  g,  and  the  anterior  interosseous, 
h,  appear  near  the  wrist;  but  they  belong  to  the  deeper  dissection,  with 
which  they  will  be  described. 


ILLUSTKATIONS    OF    DISSECTIONS. 


DESCRIPTION'  OF  PLATE  XII. 


The  deep  muscles  of  the  back  of  the  forearm  and  the  posterior  inter- 
osseous artery  and  nerve  are  pictured  in  this  Plate. 

The  superficial  muscles  have  been  cut  through  near  their  origin,  with 
the  excej)tion  of  the  supinator  longus  on  the  one  side,  and  the  anconeus 
on  the  other.  In  reflecting  the  extensors  of  the  fingers,  the  branches  of 
vessels  and  nerves  to  them  should  be  defined  at  the  same  time. 


DEEP  MUSCLES. 


In  the  group  of  deep  muscles  at  the  back  of  the  forearm  are  included 
three  extensors  of  the  thumb,  the  special  extensor  of  the  fore  finger,  and 
the  short  supinator. 


A.  Supinator  brevis. 

B.  Extensor  ossis   metacarpi  polli- 

cis. 

C.  Extensor  primi  internodii  poUi- 

cis. 

D.  Extensor  secundi  internodii  pol- 

licis. 

E.  Extensor  proprius  indicis. 

F.  Extensor  longus  digitorum,  cut. 

G.  Extensor  carpi  ulnaris.- 


H.  Anconeus  muscle. 
K.  Extensor  carpi  radialis  brevior. 
L.  Extensor  carpi  radialis  longior. 
M.  Supinator  longus. 
N.  Brachialis  anticus. 
P.  Biceps  brachii  muscle. 
R.  Triceps  brachii  muscle. 
S.  Posterior  annular  ligament. 
f  External  lateral  ligament  of  the 
elbow-joint. 


The  supinator  hrevis,  A,  nearly  encircles  the  upper  part  of  the  radius, 
and  is  the  highest  of  the  deep  muscles.  It  arises  from  the  ulna  below 
the  small  sigmoid  notch,  from  the  orbioular  ligament  of  the  radius,  and 
from  the  external  lateral  ligament  of  the  elbow-joint.  The  fibres  curve 
forwards  and  downwards,  and  are  inserted  into  the  radius  so  as  to  cover 
that  bone  as  low  as  the  pronator  teres,  except  along  a  triangular  surface 
on  the  inner  side:  the  lowest  fibres  taper  to  a  point  externally,  and  the 
highest  inclose  the  neck  of  the  radius. 


PLATE  XI 


^K  X 


'\kK% 


X 


XTL-^ 


\/* 


\|'|  'tv, 


^15K 


V*-  , 


Vkju^ 


'^k.    ^ 


v^^"":*;. 


DEEP    MUSCLES    OF   THE   FOREARM.  99 

The  connections  of  the  supinator  with  muscles,  vessels,  and  nerves, 
are  numerous  and  complicated.  An  anterior  view  of  the  muscle  is  given 
in  Plate  ix.  Perforating  the  muscular  fibres  is  the  posterior  interosseous 
nerve;  and  the  posterior  interosseous  artery  appears  at  the  lower  bor- 
der. 

The  muscle  turns  the  upper  end  of  the  radius  backwards,  and  supi- 
natcs  the  hand.  It  is  the  direct  antagonist  with  the  biceps  of  the  pronator 
teres;  and  in  consequence  of  the  attachment  of  both  muscles  near  the 
upper  end  of  the  radius,  they  keej)  the  upper  fragment  supinated  in 
fracture  of  the  shaft  of  the  bone. 

Extensor  ossis  metacarjji  poinds,  B,  the  largest  of  the  thumb  exten- 
sors, arises  from  both  bones  of  the  forearm,  and  from  the  interosseous 
membrane,  viz.,  from  three  inches  of  the  radius  below  the  supinator,  and 
from  a  narrowed  surface  of  the  ulna  of  about  the  same  length,  and  close 
to  the  outer  edge. 

In  company  with  the  next  extensor  it  occupies  the  outer  compartment 
of  the  annular  ligament;  and  it  is  inserted  into  the  base  of  the  metacarpal 
bone  of  the  thumb,  and  into  the  os  trapezium  (Theile). 

It  moves  the  thumb  out  of  the  hollow  of  the  hand  towards  the  radius, 
hence  the  origin  of  the  term  abductor  Avhich  has  been  given  to  it.  After 
the  thumb  is  drawn  backwards,  the  muscle  will  assist  in  the  extension  of 
the  radial  side  of  the  wrist. 

The  exte7isor  primi  intemodii  j^ollicis,  C,  is  the  smallest  of  the  ex- 
tensors, and  arises  from  one  bone  and  the  interosseous  membrane — being 
attached  to  the  posterior  surface  of  the  radius  for  about  an  inch,  but  to 
rather  more  of  the  membrane.  After  passing  through  the  annular  liga- 
ment, the  muscle  is  inserted  into  the  base  of  the  nearest  phalanx;  its 
tendon  is  united  often  with  that  of  the  extensor  of  the  metacarpal  bone. 

Its  primary  action  is  to  extend  the  nearest  joint  of  the  thumb;  and 
contracting  still  more,  the  muscle  will  extend  the  wrist-joint. 

Extensor  secundi  internodii  polUcis,  D,  arises,  like  the  preceding, 
from  only  one  bone  and  the  interosseous  membrane,  and  chiefly  from  an 
impression  on  the  ulna  about  four  inches  long,  which  lies  inside  that  for 
the  extensor  ossis  metacarpi.  Contained  in  a  separate  sj^ace  in  the  an- 
nular ligament,  the  tendon  is  continued  over  the  back  of  the  wrist,  and 
the  radial  extensors  of  that  joint,  to  its  insertion  into  the  base  of  the  last 
phalanx  of  the  thumb. 

The  muscle  will  extend  the  last  joint  of  the  thumb;  and  it  can  after- 


100 


ILLUSTRATIONS   OF   DISSECTIONS. 


wards  assist  the  other  extensors  in  moving  backwards  the  thumb,  and 
extending  the  wrist. 

Extensor  indicis,  E.  The  indicator  muscle  arises,  inside  the  preced- 
ing, from  the  shaft  of  the  ulnar  for  three  or  four  inches  below  the  middle 
(in  length),  though  reaching  sometimes  as  high  as  the  anconeus.  Passing 
through  the  annular  ligament  with  the  common  extensor,  it  is  directed  to 
the  fore  finger,  where  it  joins  on  the  first  phalanx  the  common  tendinous 
expansion  (p.  93). 

The  name  expresses  its  action  on  the  fore  finger.  If  all  the  fingers 
are  opened  together,  it  assists  the  common  extensor.  When  the  fore 
finger  is  straightened,  the  other  digits  being  closed,  this  muscle  alone 
points  the  finger;  for,  during  the  act,  the  part  of  the  common  extensor 
to  that  finger  is  passive,  being  drawn  out  of  the  line  towards  the  second 
finger  by  the  fibrous  band  connecting  the  two  outer  pieces  of  the  extensor 
tendon. 

Supinator  longus,  M.  In  this  Plate  the  peculiar  shape  of  the  upper 
part  of  the  muscle,  and  the  way  in  which  it  curves  over  the  long  extensor 
of  the  wrist  to  touch  the  short  extensor,  can  be  observed. 

The  posterior  annular  ligament,  S,  is  described  with  Plate  xi.  In 
the  dissection  the  sheath  containing  the  common  extensor  of  the  digits 
was  opened  to  trace  the  ending  of  the  posterior  interosseous  nerve  on  the 
back  of  the  wrist. 


ARTERIES  AT  THE  BACK  OF  THE  FOREARM. 

The  posterior  interosseous  artery,  and  the  ending  of  the  anterior 
interosseous  artery  and  some  of  its  offsets,  ramify  amongst  the  muscles 
on  the  back  of  the  forearm.  Opposite  the  elbow  joint  the  radial  recur- 
rent artery  is  directed  backwards  to  the  superficial  muscles. 


a.  Posterior  interosseous  artery. 
h.  Recurrent  interosseous. 

c.  Communicating    branch,    to    tlie 

anterior  interosseous. 

d.  Continuation  of  the  posterior  in- 

interosseous  artery. 


e,  e.  Perforating  offsets  of  the  ante- 
rior interosseous. 
/, /,  Terminal  parts  of  the  anterior 
interosseous. 
g.  Recurrent  radial  artery. 
h.  Trunk  of  the  radial  artery. 


The  posterior  iiiterosseous  artery  springs  from  the  common  interos- 
seous trunk  in  front  of  the  limb  (p.  76,  Plate  ix.),  and  bends  back  above 


NERVE  OF  THE  BACK  OF  THE  FQREARM. 


101 


ilie  interosseous  membrane.  Appearing,  behind,  between  the  supinator, 
A.,  and  extenso/  ossis  metacar]Di,  B,  it  is  directed  between  the  superficial 
and  deep  strata  of  the  muscles  as  far  as  the  lower  third  of  the  forearm: 
here  it  becomo-'i  superficial,  and  courses  along  the  tendon  of  the  extensor 
carpi  ulnaris,  "Gr,  to  the  wrist,  where  it  ends  in  offsets,  which  communi- 
cate with  tJy.^  anterior  interosseous,/,  and  with  the  posterior  carpal,  b 
(Plate  xi.).      (ts  named  branches  are  recurrent  and  muscular. 

MusciJii'  branches  supply  the  deep  layer,  and  the  digital  and  ulnar 
extensors  oi  the  superficial  layer;  those  to  the  superficial  layer  have  been 
cut  in  <lelaching  the  muscles. 

TV  recurrent  branch,  b,  ascends  between  the  supinator,  A,  and  anco- 
neicP,  H;  and  supplying  both  muscles,  anastomoses  with  the  superior 
proi^unda  artery.     (Plate  vii.) 

The  anterior  interosseous  artery,  f,  comes  from  the  front,  through  an 
aperture  in  the  lower  part  of  the  interosseous  membrane,  and  ends  on 
the  back  of  tlie  wrist,  anastomosing  with  the  posterior  carpal  and  inter- 
osseous arteries;  it  gives  a  considerable  offset  to  the  outer  side  of  the  wrist. 

Perforating  branches  of  the  anterior  interosseous  arterj^,  e,  e,  three  or 
four  in  number,  pierce  the  interosseous  membrane,  and  anastomose 
together  as  well  as  with  the  ending  of  the  anterior  interosseous,  /. 

Recurrent  artery,  g,  of  the  radial,  ascends  beneath  the  supinator  lon- 
gus,  M,  and  communicates  with  the  upper  profunda  in  the  arm.  (Plate 
vii.)  It  supplies  the  supinator,  and  the  radial  extensors  of  the  wrist, 
also  the  brachialis  anticus;  and  a  considerable  offset  enters  the  supinator 
brevis.  A,  and  communicates  with  the  recurrent  interosseous. 

Radial  artery,  li.  The  anatomy  of  the  trunk  and  branches  of  this 
artery  on  the  back  of  the  wrist  and  hand  has  been  given  in  the  descrip- 
tion of  Plate  xi.,  to  which  reference  may  be  made. 


NERVE  OF  THE  BACK  OF  THE  FOREARM. 

The  musculo- spiral  nerve  supplies  the  extensor  and  supinator  muscles 
of  the  back  of  the  forearm. 


1.  Musculo-spiral  trunk. 

2.  Radial  nerve. 

3.  Posterior  interosseous. 

4.  Branch  to  the  two  first  extensors 

of  the  tliumb. 


5.  Branch  to  the  third  extensor  of  the 

thumb  and  the  indicator  muscle. 

6.  Continuation  of  the  posterior  in- 

terosseous nerve. 

7.  Gangliform    enlargement    of    the 

nerve  on  the  wrist. 


102  ILLUSTRATIONS    OF    DISSECTIONS. 

The  trunk  of  the  onusculo-spiral  nerve,  1,  has  been  traced  through 
the  triceps  to  the  outer  part  of  the  arm,  (Plate  vii.)  Guided  after- 
wards by  the  long  supinator,  M,  and  resting  on  the  brachialis,  N,  it 
reaches  the  outer  condyle  of  the  humerus,  and  divides  into  two — radial 
and  posterior  interosseous.  Branches  from  it  enter  tlie  tAvo  muscles 
mentioned,  also  the  long  extensor  of  the  wrist,  and  sometimes  the  short 
extensor. 

The  radial  nerve,  2,  has  solely  a  cutaneous  distribution,  and  ends  in 
the  integuments  of  the  back  of  the  hand,  and  the  three  outer  digits. 

^\lq 'posterior  interosseous  nerve,  3,  pierces  the  supinator  brevis,  and 
runs  between  the  two  strata  of.  muscles  to  the  middle  of  the  forearm. 
Then  sinking  under  the  extensor  of  the  second  phalanx  of  the  thumb,  it 
is  continued  on  the  interosseous  membrane  to  the  back  of  the  wrist, 
where  it  swells  into  a  reddish  gangliform  body,  7,  under  the  tendons  of 
the  common  extensor,  and  gives  offsets  to  the  articulations. 

All  the  muscles  of  the  deep  layer,  and  those  of  the  superficial  layer, 
except  these  three  anconeus,  long  supinator,  and  long  radial  extensor  of 
the  wrist — receive  branches  from  this  nerve. 

As  the  nerve  supplies  the  extensors  and  supinators  of  the  forearm, 
injury  or  disease  of  it  may  be  attended  by  paralysis  of  those  muscles;  and 
as  the  flexor  and  pronator  muscles  in  front,  supplied  by  different  nerves 
(median  and  ulnar),  would  then  be  unopposed  in  their  action,  they  would 
determine  the  position  of  the  limb.  Consequently,  after  the  function  of 
the  nerve  is  destroyed,  the  hand  would  be  pronated,  the  wrist  bent,  and 
the  fingers  semiflexed  by  the  action  of  the  anterior  group  of  muscles  on 
the  joints.     This  state  of  the  limb  is  seen  in  the  colic  of  painters. 

With  the  subjoined  concise  notice  of  the  general  arrangement  of  the 
muscles,  vessels,  and  nerves  of  the  arm,  and  of  the  similarity  between 
the  two  limbs,  the  anatomy  of  the  upper  limb  will  be  brought  to  an 
end. 

The  upper  has  its  counterpart  in  the  lower  limb;  and  with  the  palm 
of  the  hand  up,  the  front  of  the  upper  limb  is  represented  by  the  back  of 
the  lower;  and  the  opposite. 

The  movements  of  the  joints  have  a  close  resemblance  in  the  two 
members;  but  the  scapula  and  radius,  possessing  special  movements,  are 
provided  with  some  muscles  which  are  not  required  in  the  buttock  and 
the  \Qg. 


SUMMARY    OF   THE    VESSELS    AND    NERVES.  103 

As  all  the  joints  in  the  ujiper  limb  bend  forwards,  the  flexors  occupy 
the  anterior,  and  the  extensors  the  posterior  surface;  contrary  to  their 
position  in  the  lower  limb  on  the  opposite  aspects  of  each  segment. 

The  vessels  have  a  ramified  distribution  in  the  limbs — the  branches 
diminishing  in  size,  and  increasing  in  number  towards  the  digits,  in  the 
same  way  as  the  bones. 

The  offsets  of  the  artery,  unobstructed  by  valves.  Join  freely  together, 
and  form  larger  and  more  frequent  anastomoses  the  nearer  they  approach 
the  digits;  and  in  this  way  provision  is  made  for  the  onward  course  of 
the  blood  even  when  the  trunks  may  be  closed. 

The  veins  are  provided  with  valves,  which  prevent  a  backward  flow 
of  the  blood  in  them;  and  they  are  also  united  by  collateral  branches, 
so  that  the  circulating  fluid,  stopped  in  one  vessel,  may  be  carried  upwards 
more  or  less  perfectly  by  another  channel.  Besides  the  deep  veins,  which 
are  more  numerous  than  the  arteries  they  accompany,  superficial  veins 
ramify  in  the  subcutaneous  fat:  both  sets  join  at  intervals. 

In  both  limbs  the  nerves  divide  and  decrease  in  size,  like  the  arteries; 
but  the  branches  are  very  constant,  and  regular  in  their  distribution: 
they  seldom  join  each  other,  unless  they  are  subcutaneous. 

All  the  nerves  of  the  upper  limb,  with  the  exception  of  a  few  in  the 
integuments  of  the  shoulder  and  inner  side  of  the  arm,  come  from 
the  brachial  plexus.  Each  of  the  larger  nerves  sup^^lies  muscles  and 
integuments.  The  smaller  ones  end  altogether  in  the  muscles  about  the 
shoulder.  And  two  (large  and  small  internal  cutaneous)  belong  solely 
to  the  teguments. 

Three  nerves  reach  the  fingers : — of  these,  one  (musculo-spiral)  ends 
on  the  dorsum;  and  the  other  two  (median  and  ulnar)  ramifying  on  the 
palmar  surface  of  the  digits,  constitute  specially  the  neiTcs  of  touch. 

The  three  large  nerves  last  mentioned  supply  most  of  the  muscles 
below  the  shoulder: — the  musculo-spiral  being  distributed  to  the  exten- 
sors and  the  supinators,  and  to  one  flexor  in  part  (brachialis  anticus) ;  and 
the  ulnar  and  median  giving  branches  to  the  flexors  and  the  pronators. 


104:  ILLD8TEATION8    OF   DISSECTIONS. 


ILLUSTRATIONS  OF  THE  HEAD  AXD  ]\^ECK. 


DESCRIPTIOX  OF  PLATE  XIII. 


The  base  of  the  skull,  with  the  cranial  nerves,  and  the  first  and  second 
stages  of  the  dissection  of  the  orbit,  may  be  studied  with  the  aid  of  this 
Figure. 

After  the  removal  of  the  brain,  the  fossae  and  the  dura  mater  in  the 
base  of  the  skull  are  visible  without  further  preparation;  but  the  dissec- 
tion required  for  the  display  of  the  cranial  nerves  and  the  contents  of  the 
orbit  will  be  subsequently  described. 


BASE  OF  THE  SKULL  AND  THE  DURA  ilATER. 

The  region  called  base  of  the  skull  is  situated  inside  the  cranium,  and 
lies  below  the  level  of  a  line  carried  circularly  round  the  head  from  the 
superciliary  eminences  in  front  to  the  occipital  protuberance  behind.  It 
is  divided  into  three  fossa  on  each  side  of  the  middle  line;  and  a  strong 
fibrous  membrane,  the  dura  mater,  lines  the  whole. 


A.  Middle  fossa  of  the  base. 

B.  Posterior  fossa. 

C.  Superior  occipital  fossa. 

D.  Part     of     the     tentorium,     cut 

through. 

E.  Part  of  the  falx  cerebri,  also  cut. 


F.  Falx  cerebelli. 

G.  Straight  sinus. 

H.  Cribriform  plate  of  the  ethmoid 

bone. 
I.  Crista  galli  of  the  ethmoid  bone. 
K.  Roof  of  the  orbit  raised. 


The  anterior  fossa  of  the  base  lies  over  the  orbit,  and  must  be  de- 
stroyed nearly  altogether  by  the  dissection  of  that  space.  For  the  most 
part  the  surface  of  the  fossa  is  convex,  but  along  the  middle  line  it  is 
hollowed  where  it  lodges  the  olfactory  bulb:  at  the  forepart  of  the  hollow, 
H,  small  apertures  exist  in  the  cribriform  plate  of  the  ethmoid  bone  for 


PLATE  X 


:^^ 


BASE   OF   THE   SKULL   AND    THE    DURA    MATER.  105 

the  transmission  of  the  olfactory  nerve  filaments  to  the  nose.  On  the 
anterior  fossa  rest  the  frontal  lobes  of  the  large  brain. 

The  middle  fossa,  A,  receives  the  middle  part  of  the  cerebrum  or 
large  brain.  Much  deeper  than  the  anterior  fossa,  its  bottom  will  reach 
down  to  a  level  with  the  articulation  of  the  lower  jaw.  Along  the  mid- 
dle line  is  the  depression  (sella  Turcica)  on  the  body  of  the  sphenoid  bone 
containing  the  pituitary  body.  Small  vessels  ramify  in  the  fossa;  and 
the  internal  carotid  artery  and  some  cranial  nerves  cross  the  inner  end. 

The  posterior  fossa,  B,  is  more  extensive  than  the  others,  being  wide 
and  shallow,  and  contains  the  hemispheres  of  the  small  brain  or  cerebel- 
lum. Its  depth  will  be  marked  on  the  side  of  the  head  by  the  tip  of  the 
mastoid  process.  In  its  centre  is  the  large  foramen  magnum  transmit- 
ting the  spinal  cord. 

If  the  skull  has  not  been  sawn  so  low  as  the  occipital  protuberance, 
there  will  be  another  depression  at  the  base,  the  superior  occipital  fossa, 
C,  in  which  the  posterior  end  or  the  occipital  lobe  of  the  large  brain 
rests. 

Dura  mater.  This  is  a  strong  fibrous  membrane,  which  serves  as  an 
endosteum  to  the  bone,  and  supports  parts  of  the  brain.  Its  vessels  and 
nerves  are  named  meningeal.  Three  chief  processes  project  inwards 
between  parts  of  the  brain:  two  of  these  are  met  with  in  the  examination 
of  the  base  of  the  skull,  and  the  third  occupies  the  middle  line  of  the 
head  above  the  occipital  protuberance. 

The  tentorium  cerehelli,  D  (Plate  xiv.),  is  arched  over  the  posterior 
fossa  of  the  base,  leaving  only  a  small  aperture  in  front  for  the  commu- 
nication of  the  spinal  cord  with  the  brain;  and  it  is  interposed  between 
the  large  and  small  brains.  Uniting  with  it  along  its  middle,  above  and 
below,  are  folds — the  falx  cerebri  and  falx  cerebelli,  which  keep  it  fixed 
tightly.     In  its  centre  is  a  triangular  venous  space,  the  straight  sinus,  G. 

T\\efalx  cerelelli,  F,  reaches  from  the  occipital  protuberance  to  the 
foramen  magnum,  and  is  widest  where  it  joins  the  tentorium.  It  con- 
tains the  occipital  sinus. 

Falx  cerebri,  E.  Only  a  small  part  of  this  is  exhibited.  It  is  nar- 
rowed in  front  and  widened  behind,  and  reaches  along  the  middle  line  of 
the  head  from  the  crista  galli,  I,  to  the  occipital  protuberence  where  it 
joins  the  tentorium  (Plate  xiv.).  At  its  attachment  to  the  skull  lies  a 
venous  space,  the  superior  longitudinal  sinus  (Plate  xiv.  0). 

3Ieningeal  arteries.     Small  in  size  and  few  in  number,  they  ramify .  in 


106 


ILLUSTRATIONS    OF    DISSECTIONS. 


tlie  dura  mater  of  the  fossae,  taking  the  names  anterior,  middle,  and  pos- 
terior, from  their  situation.  Few  of  them  are  seen  in  an  ordinary  injection 
and  they  will  be  noticed  more  fully  after  the  cranial  nerves. 

Meningeal  nerves.  These  are  smaller  than  the  arteries,  and  cannot 
be  perceived  without  steeping  the  dura  mater  in  acid:  they  are  derived 
from  the  sympathetic,  and  from  some  of  the  cranial  nerves,  especially  the 
fifth. 

CRANIAL  NERVES  IN  THE  BASE  OF  THE  SKULL. 

All  the  nerves  attached  to  the  encephalon  are  called  cranial;  and  one 
nerve,  11,  not  attached  to  the  encephalon,  is  reckoned  as  a  cranial  nerve, 
because  it  enters  the  skull  and  leaves  by  an  aperture  in  the  base  of  the 
cranium.  The  nerves  course  forwards  from  their  origin  to  the  apertures 
of  exit;  and  a  part  of  each  nerve  is  left  in  the  skull  after  the  removal  of 
the  brain. 

The  nerves  crossing  the  middle  fossa  of  the  base  of  the  skull  are  in- 
vested by  sheaths  of  the  dura  mater,  but  the  others  are  free  from  the  same 
till  they  enter  their  foramina  of  exit.  On  the  left  side,  the  place  of  en- 
trance of  those  nerves  into  the  sheaths  maybe  observed;  but  to  examine 
fully  their  trunks,  and  to  define  also  the  ganglion  and  branches  of  the 
fifth  nerve,  as  in  the  Figure,  the  dura  mater  should  be  removed  on  the 
right  side  from  the  middle  fossa  of  the  base. 

There  are  twelve  pairs  of  cranial  nerves:* — these  are  marked  by  cor- 
responding numerals,  except  in  the  case  of  the  first  nerve  which  has  been 
removed  with  the  brain. 


2.  Optic  nerve  and  commissure. 

3.  Motor  nerve  of  the  eyeball. 

4.  Trochlear  nerve. 

5.  Trifacial  nerve. 

6.  Abducent  nerve  of  the  eyeball. 

7.  Facial  nerve. 

8.  Auditory  nerve. 

9.  Glosso-pharyngeal  nerve. 


10.  Pneumogastric  nerve. 

11.  Spinal  accessory  nerve. 

12.  Hypoglossal  nerve. 

13.  Gasserian  ganglion. 

14.  Ophthalmic  nerve. 

15.  Superior  maxillary  nerve. 

16.  Inferior  maxillary  nerve. 

17.  Large  petrosal  nerve. 


*  English  anatomists  reckon  in  general  nine  pairs  of  cranial  nerves,  and  the 
anatomists  on  the  Continent  enumerate  twelve  pairs;  so  that  some  confusion  in 
the  nomenclature  arises  from  this  difference  in  the  mode  of  numbering.  The 
enumeration  of  the  nerves  as  twelve  appears  most  natural,  as  only  two  nerve 


CRANIAL   NERVES   IN    THE    BASE   OF   THE    SKULL.  107 

The  olfactory,  or  first  cranial  nerve,  is  marked  by  ii  bulb  which  rests 
on  the  cribriform  plate  of  the  ethmoid  bone,  and  sends  filaments  to  the 
nose  through  the  subjacent  apertures:  it  will  be  found  attached  to  the 
brain. 

The  0})tic,  or  second  nerve,  2,  ends  in  the  eyeball.  Posteriorly  the 
nerves  of  opposite  sides  unite  in  a  commissure  (chiasma)  on  the  olivary 
eminence  of  the  sphenoid  bone,  with  a  partial  decussation  of  their  fibres. 
In  front  the  nerves  diverge;  and  each  issues  from  the  skull  through  the 
optic  foramen,  with  the  ophthalmic  artery.  In  the  orbit  of  the  left  side 
the  further  course  of  the  nerve  to  the  eyeball  is  evident. 

The  motor  ociili,  ov  third  nerve,  3,  crosses  the  middle  fossa,  and  enters 
its  sheath  of  dura  mater  behind  the  anterior  clinoid  process,  as  seen 
on  the  left  side.  Contained  in  the  dura  mater,  it  is  conveyed  to  the 
sphenoidal  fissure,  and  supplies  all  the  muscles  moving  the  eyeball,  except 
two. 

Hh.Q  troclilear ,  ov  fourth  nerve,  4,  is  received  into  sheath  of  dura  mater 
behind  the  posterior  clinoid  process,  and  courses  forwards  through  the 
wall  of  the  cavernous  sinus  to  end  in  one  muscle  in  the  orbit — superior 
oblique. 

The  trifacial,  ov  fifth  nerve,  5,  consists  of  two  roots,  large  and  small, 
though  only  the  large  root  is  visible,  for  this  lies  over  and  conceals  the 
small  root. 

The  large  root  enters  a  sheath  of  dura  mater  above  the  petrous  por- 
tion of  the  temporal  bone,  and  swells  into  a  large  ganglion  in  the  middle 
fossa  of  the  skull. 

This  ganglion,  13,  named  Gasserian,  and  about  as  large  as  the  thumb- 
nail, is  widened  in  front,  and  is  crossed  by  a  ridge  to  which  the  dura 
mater  adheres  closely.  From  the  fore  part  of  the  ganglion  three  lai'ge 
trunks  are  scut  forwards  to  end  on  the  face,  hence  the  origin  of  the  name 
of  the  nerve: — the  highest  of  these  is  the  ophthalmic  trunk,  14,  which 
passes  through  the  sphenoidal  fissure  to  the  orbit;  the  miuJle  one,  or  the 
superior  maxillary,  15,  leaves  the  skull  by  the  foramen  rotundum;  and 
the  third,  the  inferior  maxillary  nerve,  16,  issues  from  the  skull  through 


trunks,  with  like  function  and  distribution,  will  then  be  included  in  one 
cranial  pair;  whilst,  in  ixsing  the  smaller  number,  as  many  as  four  and  six  trunks, 
differing  in  name,  function,  and  distribution,  wiU  be  combined  together  as  one 
pair  of  the  cranial  nerves. 


108  ILLCrSTKATIOJSrS    OF   DISSECTIONS. 

the  foramen  ovale.  These  trunks  of  the  ganglion  confer  sensibility  on 
the  joarts  to  which  they  are  distributed. 

The  small  root  of  the  fifth  lies  under  the  large  one,  and  will  come  into 
view  on  raising  the  ganglion;  it  is  unconnected  with  the  ganglion,  and 
belongs  exclusively  to  the  inferior  maxillary  trunk.  Blending  with  off- 
sets of  the  inferior  maxillary  trunk  outside  the  skull,  it  is  conveyed  to 
muscles,  and  chiefly  to  those  of  mastication,  to  which  it  gives  the  power 
of  contracting. 

The  abducent,  or  sixth  nerve,  6,  pierces  the  dura  mater  behind  the 
body  of  the  sphenoid  bone,  and  entering  the  cavernous  sinus,  passes 
through  the  sphenoidal  fissure  to  one  muscle  (external  rectus)  of  the 
orbit. 

All  the  nerves  crossing  the  middle  fossa  of  the  base  of  the  skull, 
viz.,  the  third,  fourth,  fifth,  and  sixth,  communicate  with  the  sympathe- 
tic on  the  carotid  artery. 

The  facial,  or  seventh  nerve,  7  (portio  dura  of  the  seventh  pair, 
Willis),  enters  the  meatus  auditorius  internus.  In  the  bottom  of  that 
hollow  it  is  received  into  the  aqueduct  of  FallojDius,  and  is  conveyed  to 
the  stylo-mastoid  foramen,  where  it  escapes,  to  be  distributed  to  the  mus- 
cles of  the  face,  the  head,  and  the  ear  (in  part);  it  is  the  motor  nerve  of 
those  muscles. 

The  auditory,  or  eighth  nerve,  8  (portio  mollis  of  the  seventh  pair, 
Willis),  soft,  and  divided  into  fibrils,  accompanies  the  facial  into  the 
meatus  auditorius,  and  joasses  through  the  small  apertures  in  the  bottom 
of  that  meatus,  to  end  in  the  inner  parts  of  the  ear. 

The  glosso-pharyngeal,  or  ninth  nerve,  9  (part  of  the  eighth  pair, 
Willis),  leaves  the  skull  by  the  foramen  jugulare,  being  contained  in  a 
distinct  sheath  of  dura  mater,  and  lying  in  a  depression  in  the  lower 
border  of  the  temporal  bone.  It  is  distributed,  as  the  name  expresses,  to 
the  tongue  and  pharynx. 

The  pne^imogastric,  or  tenth  nerve,  10  (part  of  the  eighth  pair,  Wil- 
lis), is  transmitted  through  the  foramen  jugulare  in  a  sheath  of  dura 
mater  common  to  it  and  the  following  nerve.  It  is  a  flat  trunk,  consist- 
ing of  fibrils.  Its  terminating  branches  ramify  in  the  air  passages,  the 
heart,  and  the  alimentary  canal. 

The  spinal  accesory,  or  eleventh  nerve,  11  (part  of  the  eighth  pair, 
Willis),  is  the  only  cranial  nerve  that  is  not  united  with  the  encephalon. 
Arising  from  the  spinal  cord,  it  enters  the  skull  through  the  foramen 


VESSELS.  IN    THE    BASE    OF   THE    SKULL. 


109 


magnniti;  it  then  bends  outwards  to  tlic  foramen  jugulare,  and  leaves 
the  cranium  through  that  hole  in  close  contiguity  to  the  pneumogastric 
— the  two  being  contained  in  the  same  fibrous  sheath.  This  nerve  sup- 
plies in  jiart  two  muscles  of  the  neck — the  sterno-mastoid  and  trapezius. 

The  Jiyjyoglossal,  or  twelfth  nerve,  12  (ninth  pair,  Willis),  consists  of 
two  bundles  of  filaments,  which  pierce  separately  the  dura  mater.  These 
join  in  the  anterior  condyloid  foramen,  by  which  they  issue  from  the 
cranium  as  one  trunk.  It  is  a  motor  nerve  of  some  of  the  hyoid,  and 
the  tongue  muscles. 

Large  i^etrosal  nerve,  17.  This  is  a  continuation  of  the  Vidian  nerve, 
derived  from  Meckel's  ganglion.  Coming  into  the  skull  through  the 
pterygoid  foramen  and  over  the  foramen  lacerum  in  the  base,  it  is  con- 
veyed in  a  bony  groove  under  the  Gasserian  ganglion  to  the  hiatus  Fallo- 
pii,  which  it  enters  to  join  the  facial  nerve  in  the  temporal  bone. 

VESSELS  IN  THE  BASE  OF  THE  SKULL. 

Two  large  arteries  on  each  side,  carotid  and  vertebral,  j)ass  through 
the  base  of  the  skull  in  their  course  to  the  brain,  and  furnish  some  off- 
sets to  the  dura  mater.  Other  meningeal  vessels,  supplied  from  arteries 
outside  the  cavity  of  the  skull,  ramify  in  the  dura  mater. 


a.  Internal  carotid  artery. 

&.  Vertebral  artery. 

c.  Large  meningeal  artery. 


VI.  Posterior  meningeal  artery. 
n,  n.  Anterior  meningeal  arteries. 


The  internal  carotid  artery,  a,  issues  from  the  carotid  foramen  in  the 
apex  of  the  temporal  bone,  and  winding  through  the  cavernous  sinus 
(Plate  xiv.),  touches  the  brain  at  the  inner  end  of  the  fissure  of  Sylvius, 
and  splits  into  branches  (cerebral)  for  the  supply  of  the  large  brain  or 
cerebrum.  On  the  side  of  the  sphenoid  bone  it  makes  two  bends,  lying 
internal  to  the  cranial  nerves;  and  at  the  base  of  the  brain  it  is  placed 
between  the  second  and  third  nerves. 

An  ophthalmic  branch,  and  small  offsets  to  the  dura  mater,  spring 
from  this  part  of  the  carotid. 

The  vertebral  artery,  h,  is  a  branch  of  the  subclavian  trunk,  and 
enters  the  skull  through  the  foramen  magnum:  the  arteries  of  the  oppo- 
site sides  soon  coalesce,  and  they  supply  the  small,  and  part  of  the  large 
brain.     An  offset  is  furnished  by  it  to  the  dura  mater. 


110  ILLUSTEATIOXS    OF    DISSECTIONS. 

Meningeal  arteries.  Small  arteries  ramify  in  each  fossa  of  the  base 
of  the  skull;  they  are  named  anterior,  middle,  and  posterior,  like  the 
fossae. 

The  anterior  set,  two  in  number,  n,  n,  and  the  smallest,  are  branches 
of  the  ophthalmic  artery  in  the  orbit:  they  come  from  the  anterior  and 
posterior  ethmoidal  arteries,  and  entering  the  skull  at  the  edge  of  the 
cribriform  plate,  end  in  the  middle  part  of  the  fossa.  One  sends  a  twig 
to  the  front  of  the  falx  cerebri,  E. 

The  middle  set,  three  in  number  are  derived  from  branches  of  the 
external  carotid  artery,  and  appear  through  the  lacerated,  oval,  and  spi- 
nous foramina.  The  largest  of  these,  and  the  only  one  generally  injected 
is  the  following: — 

The  middle  meningeal  artery,  c,  nourishes  chiefly  the  bony  case  con- 
taining the  brain.  Arising  from  the  internal  maxillary  artery,  it  comes 
inwards  through  the  foramen  spinosum,  and  ascends  to  the  top  of  the 
head,  grooving  the  bones — more  particularly  the  lower  and  fore  parts  of 
the  parietal.  At  the  vertex  of  the  skull  it  terminates  in  the  bone,  but 
some  branches  communicate  with  the  arteries  on  the  outer  surface  of  the 
cranium. 

Branches  are  given  by  it  to  the  dura  mater.  A  petrosal  branch  enters 
the  hiatus  Fallopii  with  the  small  nerve,  17,  to  supply  the  temporal 
bone;  and  one  or  two  offsets  penetrate  into  the  orbit,  and  join  the  oph- 
thalmic artery. 

^\\Q posterior  set  includes  two  arteries:  one  is  furnished  by  the  occi- 
pital through  the  foramen  jugulare,  and  the  other,  by  the  vertebral 
artery  inside  the  skull.  Of  the  two,  the  offset,  m,  from  the  occipital  is 
the  largest,  and  it  extends  even  to  the  tentorium  cerebelli. 

Veins.  No  vein  accompanies  either  the  internal  carotid  or  the  ver- 
tebral vessels  which  end  in  the  brain;  but  companion  veins  run  with  the 
arteries  distributed  to  the  dura  mater  and  the  brain  case.  The  veins 
with  the  large  middle  meningeal  artery  may  be  plainly  seen  in  a 
dissection. 

CONTENTS    OF  THE  ORBIT. 

In  the  orbit  is  lodged  the  eyeball  with  its  muscles,  vessels,  and  nerves. 
And  the  gland  for  the  secretion  of  the  tears  is  contained  in  the  fore  part 
of  the  same  cavity. 


SUPERFICIAL    MySCLES    ANO    THE    LACHKYMAL    GLAND. 


Ill 


The  dissection  of  this  cavity  requires  some  care  in  its  execution,  in 
consequence  of  the  smaUness  of  the  vessels  and  nerves,  and  of  tlie  quan- 
tity of  fat  Avith  Avhich  they  are  surrounded. 

On  the  right  side  the  first  stage  of  the  dissection  has  been  prepared  by 
sawing  through  and  throwing  forwards  the  bony  roof;  and  then  slitting 
along  the  middle,  and  removing  the  periosteum  of  the  cavity.  On  the 
left  side,  the  cavity  having  been  opened  as  before,  the  superficial  layer 
has  been  taken  away,  to  bring  into  view  deeper  vessels  and  nerves. 


SUPERFICIAL  MUSCLES  AND  THE  LACHRYMAL  GLAND. 

The  muscles  contained  in  the  orbit  act  on  the  eyeball,  with  the  excep- 
tion of  one  which  raises  the  upper  eyelid.  Six  muscles  are-  attached  to 
the  eyeball;  of  these,  four  are  straight,  and  direct  the  pupil  to  opposite 
points  of  the  circumference  of  the  orbit;  Avhilst  two,  which  are  named 
oblique,  roll  the  ball. 


L.  Lachrymal  gland. 

M.  Eyeball  of  the  left  side. 

N.  Upper  oblique  muscle. 

P.  Levator  palpebral  superioris. 


R.  Upper  rectus  muscle. 
S.  External  rectus  muscle. 
T.  Pulley  of  the  upper  oblique  mus- 
cle. 


The  laclirymal  gland,  L,  lies  above  the  muscles  in  the  outer  part  of 
iJie  orbit,  and  touches  in  front  the  upper  eyelid.  Shaped  somewhat  like 
an  almond,  with  its  longest  measurement  directed  transversely,  it  is  sus- 
pended by  fibrous  tissue  to  the  roof  of  the  orbit.  It  secretes  the  tears-. 
and  its  ducts,  six  or  eight  in  number,  open  along  an  arched  line  on  the 
inner  surface  of  the  upper  lid,  near  the  outer  end. 

The  upper  oblique  muscle,  N  (trochlearis),  is  the  longest  muscle  in  the 
orbit,  and  passes  through  a  ring,  or  pulley.  It  arises  from  the  frontal 
bone,  close  to  the  optic  foramen  in  the  bottom  of  the  orbit;  and  ends 
anteriorly  in  a  tendon,  which  is  directed  backwards  through  the  pulley, 
but  beneath  the  upper  rectus,  and  is  inserted  into  the  eyeball  behind  the 
centre  (Fig.  xiv.). 

The  trochlea  or  pulley,  T,  is  a  ring  of  fibro-cartilage,  which  is  attached 
to  the  pit  near  the  inner  angle  of  the  frontal  bone.  A  synovial  mem- 
brane lines  the  ring,  and  fibrous  tissue  is  prolonged  from  the  margins 
along  the  tendon. 


112 


ILLUSTRATIONS    OF    DISSECTIONS. 


The  muscle  draws  inwards  somewhat  the  back  of  the  eyeball,  rotating 
it  at  the  same  time  time;  and  it  gives  to  the  pupil  an  inclination  down- 
wards and  outwards  towards  the  top  of  the  shoulder.  By  this  action  it 
is  thought  to  control  the  movement  downwards  and  inwards  of  the  eye 
by  the  inferior  rectus  muscle. 

The  levator  palpeircs  superioris,  P,  arises  in  the  bottom  of  the  orbit, 
close  to  the  preceding;  becoming  tendinous  in  front  of  the  eyeball,  it 
enters  the  ujoper  eyelid,  and  is  inserted  into  the  fore  part  of  the  tarsal 
cartilage. 

The  muscle  elevates  the  upper  eyelid,  moving  upwards  the  fibro-car- 
tilage  over  the  eyeball,  and  gives  rise  to  a  deep  groove  in  the  skin.  If 
the  eyeball  is  directed  down  when  the  muscle  is  acting,  the  elevation  of 
the  lid  is  checked  by  the  mucous  membrane  which  is  then  less  loose. 

Recti  muscles.  The  upper  rectus,  E  (attollens  oculi),  and  the  outer 
rectus,  S  (abductor  oculi),  have  a  common  origin  with  the  other  two 
recti,  around  the  optic  nerve,  at  the  apex  of  the  orbital  cavity;  and  they 
are  inserted  into  the  eyeball  about  a  quarter  of  an  inch  behind  the  cornea. 

The  outer  rectus  is  provided  with  an  additional  origin  from  a  point 
of  bone  on  the  lower  edge  of  the  sphenoidal  fissure,  near  the  inner  end 
of  that  slit:  between  this  head  and  the  common  one  the  ophthalmic  vein 
and  several  nerves  pass. 

The  pupil  is  directed  upwards  and  inwards  by  the  upper  rectus  mus- 
cle, and  outwards  by  the  other  rectus — the  insertion  of  the  muscles  into 
the  ball  in  front  of  its  greatest  transverse  diameter  impressing  on  the  eye 
the  movements  stated.  Squinting  upwards  or  outwards  may  result  from 
permanent  contraction  of  the  muscle  moving  the  eye  in  the  direction  in- 
dicated, or  from  the  rectus  in  action  being  unbalanced  through  paralysis 
of  its  antagonist  muscle  or  muscles. 

VESSELS  OF  THE   ORBIT. 


The  ophthalmic  artery  and  vein  are  represented  in  the  left  orbit. 
These  vessels  have  some  peculiarities: — they  are  not  transmitted  through 
the  same  aperture  in  the  bone;  and  the  vein,  which  is  a  single  trunk, 
ends  in  the  cavernous  sinus  in  the  interior  of  the  skull. 


d.  Ophthalmic  artery. 

e.  Anterior  ethmoidal  or  nasal  ar- 

tery. 


/.   Posterior  ethmoidal  artery. 
g.  Supra-orbital  artery. 
li.  Ophthalmic  vein. 


VESSELS    OF    THE    ORBIT.  113 

The  ophthalmic  artery,  d,  is  a  branch  of  the  internal  carotid,  and 
enters  the  orbit  through  the  optic  foramen,  lying  below  and  outside  the 
optic  nerve.  In  the  left  orbit  the.ai'tery  is  shown  coursing  over  the  optic 
nerve,  and  along  the  inner  side  to  the  front  of  the  cavity,  where  it  ends 
in  branches  for  the  root  of  the  nose  (nasal)  and  the  forehead  (frontal). 
Most  of  its  offsets  are  distributed  in  the  orbit. 

Offsets  for  the  eyeball.  Several  branches,  posterior  ciliary,  pierce  the 
back  of  the  eyeball  around  the  optic  nerve.  Other  smaller  arteries,  which 
are  usually  not  injected,  enter  the  front  of  the  ball,  close  to  the  cornea: 
these  are  the  anterior  ciliary,  and  they  are  best  seen  in  inflammation  of 
the  iris.  One  artery  enters  the  optic  nerve  behind  the  ball;  it  ramifies  in 
the  retina,  and  is  called  the  central  artery  of  the  retina. 

The  lachrymal  branch  accompanies  the  nerve,  19,  to  the  gland  of  the 
same  name. 

Muscular  branches  arise  at  intervals:  some  of  these  are  seen  in  the 
Figure. 

Eyelid  offsets.  Each  eyelid  receives  a  palpebral  branch:  these  are 
directed  transversely,  in  contact  with  the  tarsal  cartilages,  and  anastomose 
externally  with  the  lachrymal — forming  an  arch  in  each  lid. 

Brandies  leaving  the  orbit.  Besides  the  two  terminal  branches  (frontal 
and  nassal),  three  others  leave  the  cavity.  One  anterior  ethmoidal,  e,  ac- 
companies the  nassal  nerve  to  the  nose,  and  supplies  meningeal  offsets. 
Another,  posterior  ethmoidal,  f,  smaller  than  the  preceding,  passes 
through  the  foramen  of  the  same  name  to  the  dura  mater  in  the  anterior 
fossa  of  the  skull.  And  the  third,  supra-orbital,  g,  runs  with  the  nerve 
of  the  same  name  through  the  supra-orbital  notch  to  the  forehead. 

The  ophthalmic  vein,  h,  taking  the  same  general  course  as  the  artery, 
joins  in  front  the  facial  vein;  and  as  its  branches  correspond  mostly  with 
those  of  the  artery  few  are  delineated.  At  the  back  of  the  orbit  it  leaves 
the  artery,  and  passing  between  the  heads  of  the  outer  rectus,  ends  in  the 
cavernous  sinus  in  the  skull  (Plate  xiv.  Q). 

Eyeball  veins: — These  differ  from  the  arteries  of  the  ball  in  their 
number  and  course.  Four  in  number,  they  issue  on  opposite  sides  of  the 
eye,  and  about  midway  between  the  cornea  and  the  entrance  of  the  optic 
nerve. 


114 


LLLUSTRATIOKS    OF    DISSECTIONS. 


NERVES  OF  THE  ORBIT. 

Eive  cranial  nerves  enter  the  orbital  cavity,  viz.  2d,  3d,  4th,  5th, 
(in  part)  and  6th;  and  all,  except  the  second  or  optic,  come  through  the 
sphenoidal  ■  fissure.  Some  end  in  the  contents  of  the  orbit,  like  the  ar- 
teries and  others  are  transmitted  through  the  cavity  to  the  nose  and  the 
forehead:  they  have  the  following  general  distribution.  The  second  or 
the  optic  belongs  to  the  eyeball.  The  third,  fourth,  and  sixth,  are  fur- 
nished to  muscles.  And  the  ophthalmic  trunk  of  the  fifth  nerve  supplies 
the  eyeball  and  the  lachrymal  gland,  and  ends  outside  the  orbit. 

The  nerves  which  are  superficial  to  the  muscles  are  displayed  on  the 
right  side,  viz.  the  fourth,  and  the  supra-orbital  and  lachrymal  branches 
of  the  fifth:  on  the  left  side  the  other  nerves  referred  to  in  the  descrip- 
tion may  be  observed. 


2.  Optic  nerve. 

3.  Third  nerve. 

4.  Fourth  nerve. 

14.  Ophthahrdc  nerve  of  the  fifth. 


18.  Supra-orbital  nerve. 

19.  Lachrymal  n6>rve. 

21.  Upper  branch  of  the  third  nerve. 
23.  Continuation  of  the  nasal  nerve. 


The  tliird  cranial  nerve,  3  (motor  oculi),  supplies  all  the  muscles  of 
eyeball  except  two,  and  enters  the  orbit  in  two  pieces  between  the  heads 
of  the  external  rectus.  The  upper  and  smaller  part,  21  (left  side),  is 
furnished  to  the  levator  palpebra,  P,  and  the  upper  rectus,  E;  the  lower 
portion  of  the  nerve  may  be  seen  in  Plate  xiv.  22. 

The  fourth  cranial  nerve,  4,  passes  through  the  sphenoidal  fissure 
above  the  muscles,  and  ends  in  the  upper  oblique,  N,  piercing  the  fibres 
of  the  muscle  on  the  surface  turned  away  from  the  eyeball. 

The  ophtliahnic  nerve,  14,  begins  in  the  Gasserian  ganglion,  13,  and 
is  continued  through  the  wall  of  the  cavernous  sinus  and  the  sphenoidal 
fissure  to  the  orbit.  It  ends  by  dividing  into  the  supraorbital,  18,  and 
the  lachrymal  branch,  19;  and  from  its  inner  side,  before  the  terminal 
bifurcation,  springs  the  nasal  nerve,  20  (Fig.  xiv.). 

The  lachrymal  nerve,  19,  the  smallest  of  the  offsets  of  the  ophthalmic 
trunk,  IS  directed  to  the  outer  part  of  the  orbit,  and  supplies  the  lachrymal 
gland  and  the  upper  eyelid. 


J^ 


^M 


:-'Wk^  *!i 


%  km.-^, 


fwrnff  i\ 


PLATE  XIV 


NERVES    OF    THE    ORBIT.  115 

The  stipra-orbiial  nerve,  18,  lies  above  the  muscles,  like  the  lachrymal, 
and  is  continued  through  the  cavity  to  the  supra-orbital  notch,  where  it 
issues  on  the  forehead,  and  supplies  the  muscles  and  the  integuments. 
From  its  inner  side  is  given  a  long  slender  branch,  supra-ti'ochlear,  to 
the  upper  eyelid  and  the  forehead;  and  as  it  turns  round  the  margin  of 
the  orbit,  small  palpebral  filaments  are  furnished  to  the  upper  eyelid. 

The  nasal  nerve  (20,  left  side)  ends  in  the  nose,  and  passes  through 
the  orbit  and  the  cavity  of  the  skull  before  it  reaches  its  destination. 
Entering  the  orbit  between  the  heads  of  the  external  rectus  (Plate  xiv.) 
it  is  continued  forwards  with  the  ophthalmic  artery  to  the  anterior  of  the 
two  foramina  in  the  inner  wall  (23,  left  side);  here  it  is  transmitted  to 
the  cavity  of  the  skull.     In  the  orbit  its  offsets  are  the  following: — 

Firstly,  there  is  a  slender  communicating  branch  to  the  lenticular 
ganglion  (Plate  xiv.  26).  As  it  crosses  the  oj^tic  nerve  two  or  three  fila- 
ments, lo7ig  ciliary,  are  furnished  to  the  eyeball.  And  as  it  leaves  the 
orbit  it  gives  a  branch — infra-trochlear,  24,  to  the  upper  eyelid  and  the 
side  of  the  nose. 

The  nasal  nerve  is  distributed  finally  to  the  mucous  membrane  of  the 
front  of  the  nasal  cavity,  and  to  the  integuments  of  the  end  of  the  nose. 
Irritation  of  it  in  the  nasal  cavity,  as  in  taking  snuff,  induces  sneezing 
for  the  purpose  of  removing  the  irritating  body. 

Sixth  cranial  nerve,  6.  The  ending  of  this  nerve  in  the  external 
rectus  is  delineated  in  Fig.  xiv. 


DESCRIPTION  OF  PLATE  XIV. 


In  the  Drawing  a  view  is  obtained  of  the  dura  mater  at  the  base  of 
the  skull,  with  the  cavernous  sinus;  and  the  dissection  of  the  orbit  is 
carried  through  its  two  deeper  stages. 

Parts  delineated  in  this  and  the  preceding  Plate  are  marked  by  the 
same  letters  and  figures. 


116  ILLUSTRATIONS    OF   DISSECTIONS. 


THE  DURA  MATER  WITH  THE  SINUSES. 

The  tentorium  cerebelU,  D,  has  been  left  entire  for  the  purpose  of 
showing  the  height  and  extent  of  this  partition.  Its  position  will  be 
marked  on  the  surface  by  a  line  on  a  level  with  the  part  of  the  ear  joining 
the  side  of  the  head. 

Venous  spaces  occupy  the  middle  part,  and  the  attached  edge  of  the 
membrane;  and  one  of  the  largest  spaces,  called  the  cavernous,  is  close 
to  each  anterior  extremity. 

The  cave7'nous  sinus,  Q,  may  be  opened,  as  on  the  left  side,  by  cutting 
through  the  dura  mater  from  the  anterior  clinoid  process  to  the  petrous 
portion  of  the  temporal  bone,  the  cut  being  made  internal  to  the  third 
and  fourth  nerves. 

This  hollow  is  placed  on  the  side  of  the  body  of  the  sphenoid,  and 
reaches  from  the  sphenoidal  fissure  to  the  temporal  bone.  Rather  more 
than  an  inch  long,  it  measures  across  about  half  an  inch,  after  the  handle 
of  the  knife  has  been  put  into  it;  and  it  is  dilated  behind  where  it  joins 
other  sinuses.  Its  inner  boundary  is  formed  by  the  sphenoid  bone  cov- 
ered by  thin  dura  mater;  and  the  outer  boundary,  consisting  of  thickened 
dura  mater,  contains  the  third,  3,  fourth,  4,  and  the  ophthalmic  trunk 
of  the  fifth  nerve,  14,  Plate  xiii. 

Through  the  inner  part  of  the  space  pass  the  internal  carotid  artery 
and  the  sixth  cranial  nerve;  and  these  are  separated  from  the  blood  by 
the  thin  venous  lining  membrane.  Small  fibrous  bands  and  arteries  tra- 
verse the  space,  giving  rise  to  the  term  "cavernous." 

Blood  is  received  from  a  few  smaU  cerebral  veins  which  pierce  the 
outer  wall,  though  chiefly  from  the  ophthalmic  vein  (Fig.  xiii.  h)  which 
enters  in  front;  and  it  circulates  backwards  to  be  conveyed  to  the  lateral 
sinus  by  the  upper  and  lower  petrosal  sinuses.  The  blood  in  the  space 
communicates  with  that  outside  the  head  by  means  of  small  emissary 
veins,  which  penetrate  through  the  foramen  lacerum. 

Three  short  sinuses  join  the  cavernous  spaces  of  opposite  sides  across 
the  middle  line; — one  lying  before  the  pituitary  body,  one  behind  it;  and 
the  other  across  the  basilar  process  of  the  sphenoid  bone.  No  valves  exist 
in  these  cross  channels,  so  that  the  blood  can  move  freely  forwards  and 


•MUSCLES    OF    THE    ORBIT.  117 

backwards  through  them;  and  should  the  diminished  size  or  the  iibsenco 
of  one  hiteral  sinus  interfere  with,  or  stop  the  course  of  the  blood  on  that 
side  of  the  skull,  the  circulating  fluid  can  be  conveyed  across  the  middle 
line,  to  be  transmitted  from  the  head  by  the  lateral  sinus  of  the  opposite 
side. 

The  internal  carotid  artery,  a,  winds  through  the  space  from  behind 
forwards,  and  issues  through  the  dura  mater  internal  to  the  anterior 
clinoid  process:  it  furnishes  here  small  receptacular  branches  to  the  dura 
mater. 

Ascending  around  the  artery  is  the  cranial  part  of  the  sympathetic 
nerve,  which  communicates  with  the  nerves  entering  the  orbit  through 
the  sphenoidal  fissure. 

In  the  sinus  lies  the  sixth  cranial  nerve,  6,  which  courses  from  be- 
hind forwards,  close  outside  the  carotid  artery,  and  communicates  largely 
Avith  the  sympathetic. 

Another  large  central  sinus,  named  torcular  Herophili,  is  placed  op- 
posite the  occipital  protuberance,  and  receives  blood  from  the  brain. 
Opening  into  it  in  front  is  the  straight  sinus  Gr  (Plate  xiii.);  above  is  the 
superior  longitudinal,  0;  and  below  is  the  occipital  sinus  contained  in 
the  falx  cerebelli.  On  each  side  issues  the  large  lateral  sinus,  which  ex- 
tends to  the  foramen  jugulare,  joining  there  the  internal  jugular  vein, 
and  conveys  from  the  skull  the  blood  both  of  this  and  of  the  cavernous 
sinus. 


DISSECTION  OF  THE  ORBIT. 

The  third  stage  of  the  dissection,  which  is  represented  on  the  right 
side,  will  be  obtained  by  clearing  away  the  vessels  shown  in  the  left  orbit 
in  Plate  xiii.  And  the  preparation  of  the  last  stage,  as  exhibited  on  the 
left  side,  may  be  made  by  removing  the  lenticular  ganglion  and  the  nasal 
nerve,  and  by  dividing  the  optic  nerve  and  raising  the  ends. 


MUSCLES  OF  THE  ORBIT. 

The  muscles  lying  below  and  to  the  inner  side  of  the  eyeball  act  as 
antagonists  to  the  group  of  muscles  (before  described,  p.  Ill)  on  the 
outer  side  and  above  the  ball.     Like  the  other  group  they  consist  of  two 


118 


ILLDSTKATIONS    OF   DISSECTIONS. 


straight  and  one  oblique;  and  they  are  named  inferior  rectus,  internal 
rectus,  and  inferior  oblique. 


N.  Upper  oblique  muscle. 

O.  Superior  longitudinal  sinus. 

P    Levator  palpebrge  superioris. 

Q.  Cavernous  sinus. 

E.  Upper  rectus  muscle. 


S.  External  rectus  muscle. 
V.  Inferior  rectus  muscle. 
W.  Inferior  oblique  muscle. 
X.  Internal  rectus  muscle. 


Recti  muscles.  The  lower  rectus,  V  (depressor  oculi),  and  the  inner 
rectus,  X  (adductor  oculi),  arise,  behind,  around  the  optic  nerve  with 
the  other  muscles;  and  the  two  separating  from  each  other  in  front,  are 
inserted  into  the  eyeball  near  the  cornea,  each  being  attached  opposite  its 
antagonist  muscle. 

One  of  these  muscles  contracting,  the  pupil  will  be  directed  towards 
it,  the  under  rectus  depressing  and  adducting,  and  the  inner  one  adduct- 
ing  the  eye;  but  the  two  recti  acting  together  the  pupil  will  be  turned 
to  a  point  intermediate  between  both. 

The  external  rectus,  S,  is  more  evident  here  than  in  Figure  xiii. ;  and 
on  the  right  side  the  nerves  passing  between  its  heads  of  origin,  viz.,  the 
third,  3,  the  nasal  nerve  of  the  fifth,  20,  and  the  sixth,  6,  have  been 
traced  out,  to  show  their  relative  position. 

The  inferior  oblique  muscle,  W,  is  displayed  only  at  its  insertion  into 
the  eyeball.  Arising  from  the  fore  part  of  the  floor  of  the  orbit,  close  to 
the  lachrymal  sac,  it  is  inclined  backwards  below  the  inferior  rectus  and 
the  eyeball,  and  is  inserted  into  the  back  of  the  eye  near  the  upper  ob- 
lique muscle. 

By  the  action  of  this  muscle  the  back  of  the  ball  may  be  depressed 
and  the  cornea  raised;  and  the  eye  being  rotated  at  the  same  time  the 
cornea  will  be  directed  upwards  and  outwards  towards  the  temple.  This 
movement  towards  the  outer  side  of  the  orbit  is  thought  to  counteract 
the  motion  of  the  ball  up  and  in  by  the  upper  rectus  muscle. 


DEEP  NERVES  OF  THE  ORBIT. 

The  second  nerve,  part  of  the  third  nerve,  the  lenticular  ganglion, 
and  the  sixth  nerve,  are  met  with  in  the  two  deeper  stages  of  the  dissec- 
tion of  the  orbit. 


DEEP    NERVES    OF    THE    ORBIT. 


119 


On  the  right  side  the  lenticular  ganglion  is  depicted,  with  the  optic 
nerve;  and  the  other  nerves  are  visible  on  the  left  side. 


2.  Optic  nerve. 

3.  Third  cranial  nerve. 

4.  Fourth  nerve. 

5.  Fifth  cranial  nerve. 

6.  Sixth  cranial  nerve. 
13.  Gasserian  ganglion. 

20.  Nasal  nerve  at  its  origin. 


21.  Upper  branch  of  the  tliird  nerve. 

22.  Lower  branch  of  the  third  nerve. 

23.  Nasal  nerve  leaving  the  orbit. 

24.  Infra-trochlear  nerve. 
25    Lenticular  ganglion. 

26.  Long  root  of  the  lenticular  gang- 
lion to  the  nasal  nerve. 


The  023tic  or  second  cranial  nerve,  2,  lies  in  the  middle  of  the  hollow 
included  by  the  recti  muscles,  and  enters  the  buck  of  the  eyeball  rather 
internal  to  the  centre:  it  spreads  out  in  the  nervous  stratum  of  the 
retina.  Along  it  the  ciliary  arteries  and  nerves  are  conveyed  to  the 
eyeball. 

The  ophthalmic  or  lenticular  ganglion,  25,  is  a  small,  rather  red 
body,  about  as  large  as  a  pin's  head  of  moderate  size,  which  is  situate  at 
the  back  of  the  orbit,  close  to  the  ophthalmic  artery  and  the  optic  nerve. 
Nerves  issue  fi-om  it  at  four  points  (angles) :  two  pass  backwards,  joining 
other  nerves,  and  these  are  called  roots;  and  several  nerves  are  sent  for- 
wards to  the  eyeball  along  the  optic  nerve. 

Posterior  branches. — A  long,  slender  branch — the  long  root,  26, 
joins  the  nasal  nerve,  20.  Another  thick  and  short  branch — the  short 
root — unites  watli  the  third  nerve,  22  (right  side).  Sometimes  a 
third  offset,  between  those  two,  connects  the  ganglion  with  the  sym- 
pathetic. 

The  anterior  branches  or  the  short  ciliary  nerves  to  the  eyeball, 
are  about  twelve  in  number,  and  form  two  bundles,  upper  and  lower: 
they  are  furnished  to  the  ball,  and  especially  to  the  muscular  structure 
in  it. 

The  third  cranial  nerve,  3,  splits  into  two  as  it  is  about  to  enter  the 
orbit  between  the  heads  of  the  outer  rectus.  Its  upper  piece,  21,  ends 
in  the  upper  rectus,  and  in  the  elevator  of  the  upper  eyelid. 

The  lower  and  larger  part  of  the  nerve,  22  (left  side),  divides  into 
three:  one  enters  the  inferior  rectus,  V;  the  second  belongs  to  the 
internal  rectus;  and  the  third  offset,  22  (right  side),  is  continued  below 
the  eyeball  to  the  inferior  oblique  muscle.  The  last  branch  is  joined 
by  the  short  root  of  the  lenticular  ganglion,  and  supplies  through  that 
communication  motor  nerves  to  the  muscular  fibres  of  the  eveball. 


120  ILLUSTRATIONS    OF    DISSECTIONS. 

Paralysis  of  the  muscles  supplied  by  the  third  nerve  is  attended 
by  dropping  of  the  eyelid,  and  inability  to  raise  it;  and  the  eye  loses 
its  movements  in  certain  directions.  Supposing  its  existence  on  one 
side,  the  cornea  could  not  be  moved  vertically,  that  is  to  say,  it  could 
not  be  turned  upwards  or  downwards  by  the  elevator  and  depresses 
muscles;  it  could  not  be  drawn  inwards  horizontally  by  the  adductor; 
nor  could  it  be  inclined  upwards  and  outwards  by  the  inferior  oblique 
— all  the  muscles  needful  for  those  movements  being  supplied  by  the 
nerve,  and  being  therefore  unable  to  contract.  Only  two  movements 
would  remain,  viz.,  abduction  and  rotation  downwards  and  outwards: 
— the  former  depending  on  the  external  rectus  which  is  supplied  by  the 
sixth  nerve;  and  the  latter,  on  the  superior  oblique,  which  receives  the 
fourth  nerve. 

Double  vision  will  accompany  the  paralysis  when  an  attempt  is  made 
to  look  with  both  eyes  to  the  temple  of  the  opposite  or  healthy  side;  and 
this  occurrence  is  to  be  accounted  for  by  the  loss  of  the  muscular  control 
over  the  ball  of  the  affected  side.  In  looking  with  both  eyes  to  the 
temple  (left)  in  the  undiseased  state  of  the  muscles,  the  left  eye  will  be 
inclined  outwards  by  the  external  rectus,  and  the  right  eye  will  be 
turned  inwards,  toAvards  its  fellow,  by  the  internal  rectus.  But  in 
paralysis,  say  of  the  right  side,  the  affected  eye  cannot  be  inclined 
towards  its  fellow  in  consequence  of  the  internal  rectus  having  lost  its 
power  of  contracting,  whilst  the  healthy  or  left  eye  will  be  turned  out- 
wards by  the  external  rectus  muscle;  and  as  the  axes  of  the  eyes  are  not 
kept  parallel,  images  are  formed  on  non-corresponding  points  of  the  two 
retinse,  and  double  vision  results. 

The  sixth  cranial  nerve,  6,  enters  the  orbit  between  the  heads  of  the 
external  rectus,  lying  below  the  third  and  nasal  nerves,  and  above  the 
ophthalmic  vein:  it  is  distributed  to  the  external  rectus  muscle. 

In  paralysis  of  the  external  rectus  from  disease  of  this  nerve  the  eye- 
ball cannot  be  directed  outwards;  and  squinting  inwards  may  ensue  from 
the  absence  of  a  contracting  muscle  to  balance  the  internal  rectus. 

Orbital  Iranch  of  the  upper  maxillary  nerve.  After  the  contents 
of  the  orbit  have  been  removed,  this  small  nerve  may  be  found  in  the 
lower  and  outer  angle,  passing  through  the  orbit  on  its  way  to  the  face 
and  the  temple. 


PLATE  XV 


_  >f-§%gjs^C^ 


^.'■y_>S    vk'^^- 


^. 


MUSCLES   OF   THE    SIDE    OF   THE   IJECK,  121 


DESCRIPTION  OF  PLATE  XV. 


This  Figure  illustrates  the  anatomy  of  the  side  of  the  neck  behind 
the  sterno-mastoid  muscle. 

The  position  of  the  body  indicated  in  the  Drawing  will  be  required 
also  during  the  dissection,  viz.  the  arm  having  been  drawn  down  to 
depress  the  shoulder,  and  to  make  tense  the  neck  muscles. 

The  more  prominent  lateral  muscles  will  appear  readily  on  reflecting 
the  skin  by  the  incisions  marked  in  the  Plate,  and  on  removing  the  thin 
platysma  muscle,  and  the  deep  cervical  fascia;  but  much  time  and  care 
will  be  needed  to  make  clean,  and  to  leave  uninjured  the  deeper  nerves 
and  vessels. 

MUSCLES  OF  THE  SIDE  OF  THE  NECK. 

All  the  muscles  here  exhibited  in  part,  are  attached  below  either  to 
the  arch  formed  by  the  clavicle  and  the  scapula,  or  to  the  first  rib;  and 
above  they  are  fixed  to  the  head  and  the  spinal  column,  with  the  excep- 
tion of  the  omo-hyoid  which  is  attached  to  the  hyoid  bone.  A  hollow, 
the  posterior  triangular  space,  intervenes  between  the  two  largest  super- 
ficial muscles. 


A.  Platysma  myoides. 

B.  Sterno-cleido-mastoid  muscle. 

C.  Splenius  capitis. 

D.  Trapezius. 

E.  Levator  anguli  scapulae. 

F.  Scalenus  medius. 


G.  Scalenus  anticus. 
H.  Omo-hyoideus. 
K.  Deltoid  muscle. 
L.  Clavicle. 
N.  Pectoralis  major. 


Platysma  myoides,  A.  This  is  a  membraniform  fleshy  layer,  which 
is  contained  in  the  fatty  stratum  between  the  skin  and  the  deep  fascia. 
Arising  from  the  scapular  arch,  and  the  top  of  the  thorax  and  shoulder, 
it  crosses  the  side  of  the  neck,  and  is  inserted  into  the  base  of  the  lower 
jaw,  blending  with  muscles  of  the  face. 

It  covers  the  external  jugular  vein,  k,  and  the  lower  two  thirds  of 


122  ILLUSTRATIONS    OF    DISSECTIONS. 

the  posterior  triangular  space.  Its  fibres  are  inclined  downwards  and 
backwards  from  the  jaw  to  the  shoulder;  and  in  opening  the  external 
jugular  vein  in  venesection  the  incision  is  to  be  so  directed  as  to  cut 
them  across. 

The  sterno-deido-mastoid  muscle,  B,  crosses  the  neck  obliquely  from 
the  thorax  to  the  ear.  Below,  it  arises  from  the  first  piece  of  the 
sternum,  and  the  inner  third  of  the  clavicle  (Plate  xvii.);  and  it  is  in- 
serted above  into  the  mastoid  portion  of  the  temporal,  and  the  upper 
curved  line  of  the  occij)ital  bone. 

From  its  diagonal  position  in  the  neck  it  separates  a  triangular  hollow 
in  front  from  another  behind:  it  covers  the  great  carotid  bloodvessels 
and  the  neck  muscles,  and  is  crossed  by  superficial  nerves  and  veins.  It 
is  pierced  by  one  large  nerve — the  spinal  accessory  or  the  eleventh  cranial 
nerve,  13. 

Both  muscles  acting,  the  head  will  be  brought  forwards,  as  in 
nodding,  or  the  sternum  will  be  raised;  according  as  they  may  take  their 
fixed  point  above  or  below.  If  only  one  muscle  is  used  the  head  is 
turned  to  the  opposite  side;  but  in  combination  with  other  muscles 
attached  to  the  mastoid  process  it  can  incline  the  head  towards  the 
shoulder  on  the  same  side. 

In  wry-neck  (torticollis)  arising  from  muscular  contraction,  the 
sterno-mastoid  forms  a  hard,  tense  cord  on  the  side  of  the  neck  opposite 
to  that  to  which  the  head  is  turned.  Subcutaneous  cutting  through  of 
the  muscle  has  been  practised  to  remove  the  deformity. 

The  trapezius,  D,  attached  behind  to  the  spinal  column  and  the  head, 
is  inserted  in  front  into  the  outer  third  of  the  clavicle,  and  into  the 
acromion  process  and  the  spine  of  the  scapula. 

The  anterior  free  edge  of  the  muscle  limits  behind  the  posterior  tri- 
angular space;  it  is  thin  in  the  upper  half,  and  it  is  projected  forwards, 
as  a  point,  opposite  the  fourth  cervical  nerve  and  the  narrowed  part  of 
neck.* 

The  fore  part  of  the  trapezius  will  help  the  levator  anguli  scapulae,  E, 
in  raising  the  shoulder. 

S2}le7iius  capitis,  C.     This  small  part  of  the  splenius  muscle  appears 


*  When  this  edge  is  represented  in  Anatomical  Plates  as  straight  between  the 
upper  and  lower  attachments,  the  displaced  cx)ndition  is  delineated. 


LATERAL  MUSCLES  OF  THE  NECK.  123 

in  the  posterior  triangular  space,  where  it  arches  forwards  from  the  spinal 
column  to  the  mastoid  process. 

Taking  its  fixed  point  behind,  it  can  turn  the  face  to  its  own  side;  oi 
acting  with  the  sterno-mastoid,  it  will  incline  the  head  to  the  shoulder. 
When  the  muscles  of  opposite  sides  act  together,  the  head  will  be  carried 
backwards. 

Levator  anguli  scapulcs,  E,  occupies  the  hinder  part  of  the  triangular 
space.  It  arises  from  the  transverse  processes  of  the  three  or  four  upper 
cervical  vertebrse,  and  is  inserted  into  the  base  of  the  scapula  (Plate  v.  C); 
its  processes  of  origin  may  remain  separate  for  some  distance  as  in  the 
Plate,  and  appear  like  distinct  muscles. 

Its  ordinary  action  is  manifested  in  shrugging  the  shoulders;  in  this 
movement  it  is  assi-sted  by  the  upper  part  of  the  trapezius. 

The  omo-hyoideus  is  a  double-bellied  muscle,  which  reaches  from  the 
scapula  to  the  hyoid  bone,  and  is  tendinous  beneath  the  sterno-mastoideus 
(Plate  xviii.):  for  the  anatomy  of  the  anterior  belly,  see  Plate  xvii. 

The  fibres  of  the  posterior  belly,  H,  are  attached  beneath  the  trape- 
zius to  the  upper  border  of  the  scapula,  close  to  the  notch  in  that  bone; 
and  they  end  in  front  in  the  intermediate  tendon.  This  belly  crosses 
the  j)osterior  triangular  space,  cutting  off  a  small  ]3art  below,  which  con- 
tains the  subclavian  artery;  and  it  is  kept  in  place  by  a  sheath  of  the 
cervical  fascia. 

This  belly  of  the  muscle  makes  tense  the  deep  fascia  of  the  neck. 
The  possibility  of  its  compressing  the  internal  jugular  vein  has  been  sug- 
gested by  Theile.* 

The  scaleni  muscles,  three  on  each  side,  pass  from  the  first  two  ribs 
along  the  side  of  the  spinal  column,  and  are  crossed  by  the  great  nerves 
and  vessels  of  the  upper  limb. 

The  anterior  muscle,  Gr,  arises  from  the  first  rib  around  a  slight  prom- 
inence on  the  upper  surface;  and  it  is  inserted  into  the  fore  part  of  the 
transverse  processes  of  four  cervical  vertebrge,  viz.,  6,  5,  4,  3. 

In  front  of  the  muscle  lie  the  omo-hyoideus,  11,  and  sterno-mastoid- 
eus, B;  but  the  deep  connections  can  be  more  fully  observed  in  Plate 
xviii.  With  a  lateral  view  of  the  side  of  the  neck,  as  in  the  Figure,  jDart 
of  the  muscle  may  be  seen  in  the  posterior  triangular  space;  but  in  a 
front  view,  the  muscle  is  usually  concealed  by  the  sterno-mastoideus. 

*  "  Lehre  von  den  Muskeln,"  Leip^g,  1841. 


124:  ILLUSTEATIONS    OF    DISSECTIONS. 

The  middle  muscle,  F,  larger  tlian  the  preceding,  arises  from  a  groove 
across  the  hinder  part  of  the  upper  surface  of  the  first  rib;  and  it  is  in- 
serted into  the  posterior  part  of  the  transverse  processes  of  all  the  cervi- 
cal vertebrae. 

Along  its  outer  edge  lies  the  levator  anguli  scapulge;  and  it  is  placed 
beneath  the  cervical  nerve  trunks,  and  the  subclavian  artery. 

The  posterior  muscle  is  small,  and  is  concealed  by  the  preceding. 
Arising  from  the  upper  border  of  the  second  rib  at  the  back,  it  is  inserted 
into  the  transverse  processes  (posterior  or  neural)  of  two  or  three  lower 
cervical  vertebrae. 

"When  the  neck  is  fixed  the  scaleni  will  elevate  the  first  two  ribs. 
When  the  ribs  are  fixed  the  movements  of  the  neck  will  vary  with  the 
action  of  the  different  muscles.  If  the  two  posterior  scaleni  of  one  side 
contract,  the  neck  will  be  inclined  laterally  towards  the  muscles  acting; 
but  if  those  of  both  sides  come  into  play  at  once — the  one  set  antagoniz- 
ing the  other — the  vertebral  column  will  remain  upright.  Should  the 
anterior  scaleni  of  both  sides  act  the  neck  would  be  bent  forwards,  in 
consequence  of  their  attachment  in  front  of  the  spine. 

Another  muscle,  the  serratus  magnus,  lies  in  the  lower  and  outer 
angle  of  the  triangular  space,  viz.,  where  the  omo-hyoideus  and  the  tra- 
pezius meet;  it  is  concealed  by  the  trapezius. 

POSTERIOR  TRIANGULAR  SPACE  OF  THE  NECK. 

The  intermuscular  interval  on  the  side  of  the  neck,  named  the  pos- 
terior triangular  space,  is  narrow  before  the  fascia  is  removed,  like  the 
corresponding  hollows  opposite  the  joints,  but  in  the  Drawing  the  space 
is  delineated  as  it  appears  after  dissection.  The  great  artery  of  the  upper 
limb  with  some  smaller  branches,  and  the  cervical  nerves,  together  with 
much  fat  and  interspersed  lymphatic  glands,  are  contained  in  this  hol- 
low. 

This  interval  reaches  from  the  clavicle  to  the  back  of  the  head.  It  is 
bounded  in  front  by  the  sterno-mastoideus,  B,  and  behind  by  the  trapezius 
muscle,  D.  By  its  dissection  greater  apparent  length  is  given  to  the  neck, 
in  consequence  of  the  teguments  being  removed  from  part  of  the  head. 

Narrower  above  than  below,  the  space  is  said  to  be  triangular.  Rather 
it  is  flask-shapedj  with  the  small  part  directed  upwards.  As  low  as  the 
letter  D,  the  hollow  is  shallow,  and  the  sides  nearly  straight;  but  beyond 


POSTERIOR   TRIANGULAR   SPACE   OF   THE   NECK.  125 

that  spot  it  becomes  deeper,  and  is  widened  in  consequenae  of  the  posterioi 
border  being  curved.  When  in  its  natural  position,  the  upper  part  of  the 
sterno-mastoid  projects  farther  back  towards  the  trapezius  than  is  indi- 
cated in  the  Drawing. 

Stretched  over  the  space  are  the  skin,  the  subcutaneous  fatty  layer 
containing  the  platysma.  A,  and  the  deep  cervical  fascia.  And  the  floor 
of  the  hollow  is  formed  by  the  superficial  stratum  of  the  muscles  of  the  side 
of  the  neck,  in  the  following  order.  Beginning  above,  the  splenius  capitis, 
C,  is  first  met  with;  and  below  it  lies  the  levator  anguli  scapulge, divided  into 
parts  and  marked  by  E,  E.  Farther  down  comes  the  scalenus  medius, 
F;  and  near  the  clavicle  the  serratus  magnus  projects  above  the  first  rib, 
but  this  would  be  visible  under  the  trapezius  only  in  a  front-view. 

The  space  is  divided  into  two  unequally-sized  parts  by  the  small  omo- 
hyoideus  muscle,  H — the  lower  being  designated  clavicular,  and  the  upper 
occipital. 

The  occipital  part,  much  the  larger  of  the  two,  occupies  nearly  the 
whole  length  of  the  neck.  It  has  the  same  bounds  in  front  and  behind 
as  the  large  hollow;  and  it  is  limited  below  by  the  omo-hyoideus,  H.  Its 
depth  increases  towards  the  lower  boundary,  and  in  it  are  contained 
chiefly  nerves,  with  some  small  vessels,  and  lymphatics. 

The  nerves  issue  from  beneath  the  sterno-mastoid  muscle,  and  unite 
in  a  plexiform  manner — the  upper  nerves  entering  the  cervical,  and  the 
and  lower  the  brachial  plexus. 

From  the  nerves,  1,  and  2,  of  the  cervical  plexus,  superficial  branches 
are  directed  upwards  and  downwards: — The  ascending  set  reach  tlie  fore 
part  of  the  neck,  the  ear  and  contiguous  part  of  the  face,  and  the  back  of 
the  head;  and  the  descending  set,  more  numerous  than  the  other,  are 
continued  through  the  space  to  the  integuments  of  the  top  of  the  chest 
and  shoulder. 

The  lower  cervical  nerves  join  in  the  brachial  j)lexus,  11.     These 
trunks  are  inclined  downwards  through  the  lower  end  of  the  occipital  part, 
and  through  the  clavicular  part  of  the  triangular  space  to  the  axilla:  they 
.give  few  branches,  and  their  position  will  be  referred  to  again. 

One  large  nerve,  13,  the  spinal  accessory  (eleventh  cranial  nerve), 
crosses  the  space  obliquely  downwards  and  backwards,  from  the  border  of 
the  sterno-mastoideus  to  the  under  surface  of  the  trapezius. 

Vessels.  The  arterial  branches  are  small  in  size,  and  supply  the  sur- 
rounding muscles:  they  appear  behind  the  sterno-mastoideus.      The  low- 


126  ILLUSTRATIONS    OF    DISSECTIONS. 

est  and  largest  is  the  transverse  cervical  artery,  c,  which  passes  beneath  the 
trapezius.  Veins  accompany  the  arteries,  their  size  corresponding  with 
that  of  their  companions. 

The  clavicular  part  of  the  posterior  triangular  space  has  its  side 
formed  by  the  clavicle,  L,  and  the  omo-hyoideus,  H;  and  its  base  or  fore 
part  by  the  sterno-mastoideus,  B.  Towards  the  surface  it  is  covered  by 
the  same  layers  as  the  great  triangle;  and  the  floor  is  constructed  by  the 
scaleni  muscles,  the  serratus  magnus,  and  the  first  rib. 

Larger  before  than  behind,  it  is  placed  nearly  opposite  the  middle 
third  of  the  clavicle.  It  is  about  one  inch  and  a  half  long,  and  an  inch 
wide  in  front  after  the  dissection;  but  until  the  omo-hyoideus  has  been 
displaced,  this  muscle  Avill  lie  closer  to  the  clavicle,  diminishing  thus  the 
width.  Contained  in  it  are  the  subclavian  artery,  a,  the  brachial  plexus, 
11,  and  the  external  jugular  vein,  k,  with  their  offsets,  together  with 
lymphatics  and  the  usual  fat. 

Arteries.  The  subclavian  trunk,  a,  crosses  the  space  from  within 
out.  In  front  it  issues  from  beneath  the  anterior  scalenus,  G;  and  it 
disappears  below  beneath  the  clavicle.  Along  the  side  of  the  space 
formed  by  the  clavicle,  the  supra-scapular  vessels,  i,  lie  under  cover  of 
that  bone.  And  at  the  corner  where  the  omo-hyoideus  meets  the  sterno- 
mastoideus,  the  transverse  cervical  vessels,  c,  cross  the  hollow. 

Veins.  If  the  subclavian  vein  is  full  it  may  appear  beneath  the 
clavicle,  though  it  lies  usually  at  a  lower  level  than  the  artery.  The 
external  jugular  vein,  h,  is  directed  across  the  space,  to  join  the  subcla- 
vian vein  beloAv:  companion  veins,  I  and  n,  of  the  transverse  cervical  and 
supra-scapular  arteries  enter  it  near  the  clavicle. 

Nerves.  External  to  the  artery,  or  higher  in  the  neck  than  it,  the 
large  bundles  of  nerves  entering  the  brachial  plexus  are  directed  down- 
wards in  their  course  to  the  arm-pit:  they  have  a  deep  position  like  the 
artery,  and  occupy  the  interval  between  the  vessel  and  the  omo-hyoid 
muscle.  K"ear  the  outer  part  of  the  space  they  approach  closer  to  the 
vessel,  and  serve  as  a  valuable  guide  to  it  from  the  constancy  of  their 
position,  and  their  white  appearance  and  firm  feel.  Over  the  space 
descend  the  superficial  branches  of  the  cervical  j)lexus:  these  must  be 
divided  in  an  incision  into  the  neck. 

The  size  of  the  clavicular  part  of  the  triangular  space  varies  much 
with  the  condition  of  the  bounding  muscles.  Alterations  in  length  will 
be  determined  by  the  attachment  of  the  trapezius  and  sterno-mastoideus 


ARTERIES    IN   THE   TRIANGULAR    SPACE. 


127 


to  the  clavicle,  for  if  one  or  both  should  reach  farther  than  usual  on 
that  bone,  the  intermuscular  space  must  be  diminished  accordingly. 
The  width  will  be  dependent  upon  the  size  and  the  situation  of  the  omo- 
hyoideus,  II.  When  the  muscle  is  wide,  or  lies  close  to  the  clavicle,  the 
dimensions  from  above  down  of  the  clavicular  part  of  the  triangular  space 
will  be  less  than  when  the  muscle  is  narrow,  or  is  placed  at  a  greater 
distance  from  the  bone.  In  some  bodies  the  omo-hyoideus  arises  from 
the  back  of  the  clavicle,  and  conceals  the  subclavian  artery,  so  that  there 
is  not  any  interval  in  the  usual  place  between  the  muscle  and  the  collar- 
bone. 

Diiierences  in  depth  will  arise  from  varying  states  of  the  neighbor- 
ing parts.  In  a  long  and  thin  neck,  with  low  and  flat  clavicles,  the 
depth  is  not  so  great  as  in  a  short  and  thick  neck  with  prominent  and 
much  curved  collar-bones.  Changes  in  the  position  of  the  shoulder  will 
give  rise  also  to  variations  in  depth.  Thus  if  the  shoulder  is  depressed 
by  drawing  down  the  arm,  the  space  is  as  shallow  as  it  can  be  made; 
whilst  raising  the  shoulder  gives  to  the  hollow  its  greatest  depth.  And 
by  forcing  upwards  the  shoulder  the  clavicle  can  be  carried  as  high  as, 
or  even  higher  than  the  level  of  the  omo-hyoid  muscle  and  the  subcla- 
vian artery. 

ARTERIES  IN  THE  TRIANGULAR  SPACE. 

In  the  lower  part  of  the  triangular  space  are  contained  the  trunk  of 
the  subclavian  artery,  and  some  of  its  branches.  Towards  the  ear  are 
other  small  arteries,  which  are  derived  from  the  external  carotid  trunk. 


a.  Subclavian  artery. 

b.  Supra-scapular  artery. 

c.  Transverse  cervical  artery. 

d.  Qutaneous    branch    of  the    sub- 

clavian. 


e,  f.  Branches  of  the  ascending  cer- 
vical artery. 

g.  Posterior  auricular  artery. 

h.  Cutaneous  offset  of  the  posterior 
auricular. 


Siciclavian  artery,  a.  The  third  part  of  the  arch  of  the  subclavian 
trunk  (Plate  xviii.)  lies  in  the  clavicular  portion  of  the  posterior  trian- 
gular space;  and  it  has  the  following  anatomy. 

Its  extent  is  marked  by  the  outer  edge  of  the  anterior  scalenus,  G, 
on  the  one  side,  and  the  lower  border  of  the  first  rib  on  the  other  (below 
the  clavicle).     The  vessel  is  directed  outwards  at  first,  about  an  inch 


128  ILLUSTRATIONS    OF   DISSECTIONS. 

above  fhe  clavicle,  and  it  passes  downwards  finally  under  the  most  prom- 
inent  point  of  that  bone.  Superficial  to  the  artery  are  the  common  cover- 
ings of  the  space,  viz.,  the  skin,  the  cutaneous  fat  with  the  platysma,  and 
the  deep  fascia;  and  as  it  is  about  to  pass  under  the  clavicle  and  the 
subclavius  tlie  supra-scapular  artery  and  vein  cross  in  front.  Underneath 
the  vessel  lie  the  middle  scalenus,  F,  and  the  first  rib. 

Its  companion  vein,  subclavian,  is  arched  like  the  arter}^  (Plate  xviii.), 
but  it  is  placed  lower  in  the  neck,  and  beneath  the  clavicle.  Crossing 
the  artery  near  the  scalenus  is  the  external  jugular  vein,  Tc,  whose 
branches  may  form  a  plexus  over  it. 

The  nerves  of  the  brachial  plexus,  11,  lie  above  the  artery  near  the 
scalenus  anticus,  and  gradually  approach  it  below,  so  that,  at  the  clavi- 
cle, the  trunk  formed  by  the  last  cervical  and  first  dorsal  touches  the 
vessel,  and  may  be  mistaken  for  it  in  tlie  operation  of  tying  the  subcla- 
vian. A  small  branch,  10,  to  the  subclavius  muscle  is  directed  across 
the  artery.  Superficial  to  the  clavicular  space  are  the  descending  cuta- 
neous branches  of  the  cervical  plexus,  which  will  be  cut  in  the  operation 
for  ligature. 

Offsets  of  the  artery.  As  a  rule  this  part  of  the  subclavian  trunk 
does  not  furnish  any  named  branch.  A  cutaneous  offset,  d,  took  origin 
from  the  vessel  in  this  body,  but  it  springs  commonly  from  the  supra- 
scapular artery,  h,  near  the  external  jugular  vein. 

Compressio7i  of  the  artery.  As  the  subclavian  artery  is  uncovered  by 
muscle  whilst  it  crosses  the  triangular  space,  it  may  be  compressed  at 
the  lower  part  of  the  neck  during  life.  Its  position  is  marked  on  the 
surface  by  the  most  prominent  part  of  the  clavicle;  and  if  the  thumb  is 
j)ressed  firmly  downwards  and  backwards  behind  that  point  of  the  bone 
towards  the  first  rib,  the  circulation  in  the  vessel  may  be  stopped.  Some- 
times the  top  of  a  key  padded  may  be  used  more  advantageously  than 
the  thumb. 

Ligature  of  the  third  part  of  the  subclavian  artery  is  practised  com- 
monly for  aneurism  of  the  axillary  trunk;  and  as  this  operation  may  be 
rendered  more  difiicult  by  the  unusual  position  of  the  subclavian  ves- 
sels, and  by  unusual  states  of  the  surrounding  parts,  the  conditions  com- 
plicating it  will  be  first  reviewed.* 

*  The  summary  here  made  has  been  derived  from  the  facts  made  known  by 
Mr.  Quam's  researches  on  the  Surgical  Anatomy  of  the  Arteries,  in  the  work 
before  quoted. 


LIGATURE  OF  THE  SUBCLAVIAN.  129 

AUeratio}is  affecting  the  artery.  Commonly  the  arch  of  tlie  vessel 
rises  tibout  an  inch  above  the  clavicle  (Quain),  but  it  may  be  lowered  to 
the  level  of,  or  sink  beneath  the  bone;  and  on  the  other  hand  it  may  be 
.  elevated  as  high  as  one  inch  and  a  half  above  the  collar-bone.  Occasion- 
ally the  artery  passes  over  or  through  the  anterior  scalenus,  instead  of 
beneath  it.  When  the  artery  has  either  the  higher  level,  or  the  more 
superficial  position,  it  will  be  rendered  less  deep,  and  will  be  more  easy 
to  find  in  an  oj)eration. 

One  or  two  branches  for  the  shoulder,  viz.,  posterior  scapular  and 
supra-scapular,  may  spring  from  this  part  of  the  artery.  If  such  branch 
or  branches  should  be  seen  in  an  operation,  greater  security  against  sec- 
ondary haemorrhage  would  be  obtained  by  tying  one  or  both,  than  by 
leaving  either  free  to  convey  blood  into  or  from  the  trunk  near  the 
ligature. 

Alterations  in  the  surrounding  parts.  With  a  thin  and  long  neck 
and  a  flat  clavicle,  there  is  a  prospect  of  a  less  tedious  operation  than  in 
the  opposite  states  of  those  parts,  because  the  artery  will  be  nearer  the 
surface. 

Muscular  fibres  may  cover  the 'artery  as  before  said,  p.  126,  the  clavic- 
ular attachments  of  the  sterno-mastoid  and  the  tra23ezius  being  length- 
ened, or  the  omo-hyoid  arising  from  the  clavicle.  Also  in  axillary 
aneurism  high  in  the  arm-pit  the  clavicle  may  be  carried  upwards  con- 
siderably above  the  level  of  the  subclavian  artery.  Under  these  circum- 
stances the  operation  of  ligature  would  be  made  more  difficult,  as  the 
artery  must  be  sought  behind  the  raised  bone  in  the  one  case,  and  beneath 
the  muscular  fibres  in  the  other. 

The  subclavian  vein  rises  sometimes  as  high  as  the  level  of  the 
clavicle;  and  it  has  been  found  twice  beneath  the  anterior  scalenus  with 
the  subclavian  artery;  both  changes  in  its  position  would  cause  it  to  be 
more  endangered  in  the  steps  of  an  operation.  The  external  jugular 
may  be  moved  outwards  from  the  sterno-mastoideus  as  far  as  the  middle 
of  the  clavicle,  so  that  its  trunk  and  branches  would  lie  in  the  centre  of 
an  incision  to  reach  the  artery:  this  position  of  the  vein  may  so  interfere 
Avith  the  access  to  the  artery  as  to  render  expedient  division  of  the  vein, 
and  ligature  of  the  ends. 

Ste'ps  of  the  operation  of  ligature.     Taking  the  most  prominent  part 

of  the  clavicle  as  the  superficial  guide  to  the  position  of  the  artery,  draw 

down  the  loose  skin  of  the  neck,  and  cut  for  two  inches  and  a  half  along 
9 


130  ILLUSTRATIONS    OF    DISSECTIONS. 

the  clavicle — the  line  of  the  vessel  marking  the  centre  of  the  cut — so  as 
to  divide  on  the  bone  the  skin,  the  fat  and  the  platysma,  and  the  super- 
ficial nerves  and  vessels.*  Let  this  cut  be  next  moved  rather  above  the 
clavicle;  and  let  the  operator  divide  the  deep  fascia,  and  find  his  way 
vertically  downwards  to  the  artery,  looking  out  for  the  intermuscular 
interval  between  the  trapezius  and  sterno-mastoideus,  and  for  that 
between  the  omo-hyoideus  and  clavicle,  and  incising  any  muscular  fibres 
which  interfere  with  his  progress.  After  the  muscles  have  been  passed 
the  surgeon  proceeds  cautiously,  not  letting  the  knife  pass  beneath  the 
clavicle  to  wound  the  supra-scapular  vessels  or  the  subclavian  vein,  and 
using  at  this  stage  the  outer,  rather  than  the  inner  part  of  the  wound. 
Towards  the  inner  end  of  the  incision  the  external  jugular  vein  with 
branches  will  soon  be  met  with;  and  it  may.  be  either  drawn  inwards,  or 
divided  and  tied,  according  to  the  impediment  it  offers  to  reaching  the 
artery. 

To  find  the  artery  in  the  bottom  of  the  wound,  look  to  the  outer  end 
for  the  firm  and  white  cords  of  the  brachial  plexus,  which  serve  as  the 
deep  guide;  and  when  these  are  recognized  the  artery  will  be  found  lower 
down,  i.  e.,  between  them  and  the  first  rib.f  After  the  artery  has  been 
laid  bare  by  the  removal  of  some  fat  and  a  slight  sheath,  the  aneurism 
needle  should  be  entered  in  the  outer  angle  of  the  wound,  where  the  han- 
dle can  be  depressed  so  as  to  make  the  point  with  the  thread  turn  under 
the  vessel. 

Arterial  Iranclies.  The  smaller  arteries  laid  bare  in  the  dissection 
are  derived  from  two  arterial  trunks.  Behind  the  sterno-mastoideus 
they  are  offsets  of  the  subclavian  or  limb  artery;  and  the  branches  in 
front  of  the  muscle,  or  piercing  it  (except  the  lowest),  spring  from  the 
carotid  or  neck  artery. 

The  supra-scapular  artery,  h,  comes  from  the  first  part  of  the  subcla- 
vian trunk,  and  runs  behind  the  clavicle  with  its  vein  to  the  upper  bor- 
der of  the  scapula:  it  ends  on  the  dorsum  of  that  bone. 


*  If  such  a  superficial  vessel  as  that  marked  d,  in  the  Drawing,  should  arise 
from  the  subclavian  trunk,  division  of  it  at  this  stage  would  be  followed  by  con- 
siderable hgemorrhage,  and  ligature  of  it  would  probably  be  needed  before  the 
operation  could  be  continued. 

t  The  projection  or  tubercle  on  the  first  rib,  at  the  attachment  of  the  anterior 
scalenus  muscle,  is  said  by  some  authors  to  serve  as  the  deep  guide  to  the  vessel, 
but  this  eminence  is  seldom  prominent  enough  to  be  felt  by  the  finger. 


SUPERFICIAL    VEINS    OF    THE    NECK.  131 

An  offset  from  the  supra-scapular  to  the  integuments  arises  near  tlie 
sterno-mastoid :  in  this  instance  it  comes  from  the  third  part  of  the  sub- 
clavian, and  is  marked  d. 

Transverse  cervical  artery,  c.  It  arises  in  common  with  the  preced- 
ing, and  crossing  the  side  of  the  neck  above  the  arch  of  the  subclavian 
artery,  courses  beneath  the  trapezius:  here  it  furnishes  a  large  branch 
(suj)erficial  cervical),  and  bends  finally  along  the  base  of  the  scapula  with 
the  name  posterior  scapular,  and  supplies  the  muscles  inserted  into  the 
vertebral  border  of  that  bone. 

In  the  posterior  triangle  it  gives  many  branches  to  the  levator  anguli 
scapulte,  and  to  the  lymphatic  glands  and  the  fat. 

Two  small  arteries,  e  and/,  are  offsets  of  the  ascending  cervical  artery 
(a  branch  of  the  subclavian):  they  are  distributed  to  the  muscles  on  the 
side  of  the  neck,  and  to  the  areolar  tissue  and  the  glands  of  the  triangii- 
lar  space. 

The  posterior  auricular  artery,  g,  issues  in  front  of  the  sterno-mastoi- 
deus,  and  ascends  to  the  back  of  the  ear  and  the  contiguous  part  of  the 
head. 

A  cutaneous  offsets,  h,  courses  over  the  sterno-mastoid  muscle,  and 
accompanies  the  small  occipital  nerve. 

Perforating  branches.  After  piercing  the  sterno-mastoid  muscle 
these  small  arteries  supply  the  platysma  and  the  teguments. 


SUPERFICIAL  VEINS  OF  THE  NECK. 

In  the  neck  there  are  two  superficial  or  jugular  veins,  a  lateral  and 
an  anterior.  Only  the  lateral  vein  and  its  branches  appear  in  the  Draw- 
ing: the  other  is  figured  in  Plate  xvi. 


k.  External  jugular  vein. 
I,  Transverse  cervical  vein. 


n.  Supra-scapular  vein, 
o.  A  subcutaneous  vein. 


The  external  jugular  vein,  Tc,  conveys  blood  from  the  head  to  the  sub- 
clavian vein,  and  gathers  blood  also  from  the  superficial  parts  of  the 
neck.  It  begins  in  the  parotid  gland  by  the  union  of  the  temporal  and 
internal  maxillary  veins  (Plate  xvii.);  and  becoming  superficial,  it  de- 
scends beneath  the  platysma  muscle.  A,  to  the  lower  part  of  the  neck. 


132  ILLUSTRATIONS    OF    DISSECTIONS. 

where  it  sinks  througli  the  fascia  and  ends  in  the  subclavian  vein  (Plate 
xviii.).  Its  common  position  in  the  neck  would  be  marked  by  a  line 
from  the  angle  of  the  jaw  to  the  middle  of  the  clavicle,  though  in  the 
Plate  it  is  placed  internal  to  that  line. 

At  the  upper  part  of  the  neck  the  vein  is  small  in  size,  receiving  only 
few  branches,  but  for  an  inch  and  a  half  at  the  lower  end,  it  is  dilated 
behind  the  sterno-mastoid  muscle:  here  it  receives  yeins  from  the  shoul- 
der, viz.,  the  transverse  cervical,  I,  the  supra-scapular,  n.  and  some 
cutaneous  veins — one  being  marked  with  o.  A  pair  of  valves  exists  both 
above  and  below  the  lower  dilatation.  The  lower  pair  is  close  to  the 
clavicle,  and  is  less  complete  than  the  other,  for  it  allows  blood  to  pass 
in  a  reflex  course  from  the  subclavian  vein.  The  upper  pair  is  found 
just  after  the  vein  crosses  the  sterno-mastoid  muscle,  and  acts  perfectly, 
as  it  permits  the  blood  to  flow  only  in  one  direction — from  above 
down. 

Bloodletting  in  the  external  jugular  vein,  is  seldom  had  recourse  to 
now,  but  the  steps  of  the  operation  are  the  following:- -The  downward 
current  of  the  blood  is  stopped  by  pressure  of  the  thumb  near  the  clav- 
icle. A  cut  is  then  made  obliquely  upwards  and  backwards  across  the 
vein,  to  incise  the  vessel  and  the  fibres  of  the  platysma  to  the  necessary 
extent.  As  long  as  the  pressure  on  the  vein  remains  the  blood  issues 
through  the  opening,  but  when  the  thumb  is  removed  the  flow  stops,  be- 
cause the  blood  finds  its  way  by  the  usual  channel  into  the  subclavian. 
After  the  operation  is  finished  the  wound  is  to  be  closed  by  adhesive 
plaster. 

Under  some  conditions  air  may  enter  the  vein  during  the  operation  of 
bloodletting.  As  long  as  the  blood  runs  freely,  and  the  breathing  is 
regular,  the  accident  is  not  likely  to  happen:  but  if  the  breathing  be- 
comes labored,  or  if  the  opening  is  not  closed  as  soon  as  the  flow  of  blood 
stops,  air  may  be  drawn  into  the  vein. 

In  suspended  animation  the  external  jugular  is  sometimes  opened 
with  the  view  of  relieving  the  over-distended  right  side  of  the  heart  ;* 
and  this  practice  is  founded  on  the  fact  that  blood  will  enter  the  jugular 
below  from  the  subclavian  vein.     At  the  same  time  the  blood  can  flow 

*  A  more  general  employment  of  this  practice  is  recommended  by  Dr.  Stru- 
thers,  inapapei  "On  Jugular  Venesection  in  Asphyxia."  Edin.  Med.  Journal 
for  November,  1856. 


NERVES    IN  •  THE    POSTEEIOR   TRIANGULAR    SPACE. 


133 


downwards  through  the  anterior  juguhir  in  the  usual  way  (Plate  xviii. ), 
so  as  to  relieve  simultaneously  the  congested  heart  and  head. 


NERVES  IN  THE  POSTERIOR  TRIANGULAR  SPACE. 

Parts  of  the  cervical  and  brachial  plexuses  of  nerves,  with  one  cranial 
nerve — the  spinal  accessory,  are  included  in  the  dissection. 


1.  Third  cervical  nerve. 

2.  Fourth  cervical  nerve. 

3.  Great  auricular  nerve. 

4.  Small  occipital  nerve. 

5.  Superficial  cervical  nerve. 

6.  Superficial  descending  branches 

of  the  cervical  plexus. 

7.  Nerve  to  the  rhomboideus. 

8.  Nerve  to  the  serratus  magnus. 


9.  Branches  to  the  trapezius. 

10.  Nerve  to  the  subclavius. 

11.  Upper  part  of  the  brachial  plex- 

us. 

12.  Supra-scapular  nerve. 

13.  Spinal  accessory  nerve. 

14.  Posterior  auricular  nerve. 

f  Nerve  to  the  levator  anguli  sca- 
pulae from  the  cervic£il  plexus. 


The  cervical  plexiis  is  formed  by  the  union  of  the  upper  four  cervical 
nerves;  and  it  lies  beneath  the  sterno-mastoideus,  B,  and  on  the  levator 
anguli  scapulae,  E.  Only  the  lower  part  of  the  plexus  comes  into  the 
posterior  triangular  space,  and  from  it  spring  muscular,  and  ascending 
and  descending  tegumentary  branches. 

Ascending  Iranches.  These  consist  of  the  three  following  nerves, 
which  are  directed  to  the  ear,  the  occiput,  and  the  fore  part  of  the  neck. 

H\\&  great  auricular  nerve,  3,  courses  near  the  external  jugular  vein 
to  the  lobe  of  the  ear,  and  ends  in  the  integuments  of  the  hinder  and 
outer  parts  of  the  pinna.  One  offset  joins  the  posterior  auricular  nerve, 
14,  and  others  are  directed  forwards  to  the  integuments  over  the  joarotid 
gland:  some  long  slender  branches  pass  through  the  parotid  to  join  the 
facial  nerve  (Plate  xvii.). 

The  small  occipital  nerve,  4,  lies  along  the  posterior  border  of  the 
sterno-mastoideus,  and  perforating  the  deep  cervical  fascia  near  the  head, 
ramifies  in  the  scalp  of  the  occipital  region. 

The  superficial  cervical  nerve,  5,  is  often  represented  by  several  small 
nerves,  as  in  the  Drawing,  and  is  therefore  very  variable  m  its  size:  it  is 
distributed  to  the  platysma,  and  to  the  integuments  of  the  neck  m  front 
of  the  sterno-mastoid  muscle. 

Descending  Iranches.     The  chief  of  these,  two  or  three  in  numoer. 


134  ILLUSTEATIONS    OF   DISSECTIONS. 

belong  to  the  teguments  of  the  shoulder  and  the  upiaer  jmrt  of  the 
thorax;  but  some  offsets  are  directed  backwards  to  the  integuments  over 
the  trapezius  muscle,  from  the  claYicle  nearly  to  the  head. 

A  large  nerye,  6,  divides  into  three: — one  crosses  the  attachment  of 
the  sterno-mastoideus  to  the  clavicle,  another  lies  over  the  insertion  of 
the  trapezius  into  the  same  bone,  and  the  third  crosses  the  middle  of  the 
clavicle;  they  extend  two  or  three  inches  below  the  collar  1)one,  the  inner 
nerves  reaching  least  far. 

Muscular  offsets.  Only  a  few  of  these  are  now  visible.  One,  \,  enters 
the  levator  anguli  scapulse.  Others,  9,  pass  beneath  the  trapezius  supply- 
ing it;  and  they  join  beneath  that  muscle  with  the  spinal  accessory 
nerve,  13. 

BracMal  plexus. — The  lower  four  cervical  nerves,  and  the  first  dorsal 
nerve  (in  part),  give  rise  to  the  large  bundles  of  nerves  marked,  11;  but 
in  the  side  view  presented  to  the  Artist  the  arrangement  of  the  several 
nerves  entering  the  plexus  could  iiot  be  shown  as  in  Plate  xviii. 

The  plexus  extends  under  the  clavicle  to  the  axilla,  where  it  termi- 
nates in  nerves  for  the  upper  limb;^  and  all  the  muscular  offsets  in  the  neck 
come  from  the  fifth  and  sixth  cervical  nerves,  with  the  exception  of  small 
branches  to  the  longus  colli  and  the  scaleni. 

The  nerve  to  the  rhomboid  muscle,  7,  pierces  the  fibres  of  the  scalenus 
medius,  and  is  inclined  backwards  beneath  the  elevator  of  the  angle  of 
the  scapula. 

Nerve  to  the  serratus  magnus,  8  (posterior  thoracic).  This  nerve 
issues  through  the  scalenus  medius,  below  the  precedmg,  and  is  contin- 
ued ber,  ^th  the  cords  of  the  plexus  to  the  axilla.     See  Plate  li.,  5. 

The  nerve  to  the  suhclavius,  10,  passes  m  front  of  the  subclavian  ar- 
tery to  the  under  surface  of  its  muscle. 

The  supra-scapular  nerve,  12,  accompanies  the  omo-hyoid  muscle  to 
the  back  of  the  scapula,  and  supplies  the  supra  and  mfra-spinate  muscles, 
the  shoulder-joint,  and  the  blade  bone. 

The  two  remaining  nerves,  which  are  seen  in  this  part  of  the  neck, 
belong  to  the  cranial  set. 

The  spinal  accessory  nerve,  13  (eleventh  cranial),  pierces  the  sterno- 
mastoideus,  and  ends  in  the  trapezius,  after  crossing  the  posterior  trian- 
gular space,  where  it  joins  the  spinal  nerves.  Under  the  trapezius  it 
communicates  with  the  nerve  marked,  9,  before  it  enters  the  fleshy  mass. 

The  posterior  auricular,  14,  a  branch  of  the  facial  or  seventh  cranial 


THE 

FRED.  J.  BROCKWAY, 

LIBRARY, 

College  of  Physicians  &  Surgeons, 
New  York  Citj. 


PLATE  XV 


M 


wm 


SURFACE    VIKW    OF    THE    FKONT    OF    THE    NECK.  135 

nerye,  ascends  in  front  of  the  mastoid  process,  and  being  joined  b}^  the 
grcut  auricular  nerve,  splits  into  two: — one  piece  belongs  to  the  integ- 
uments of  the  back  of  the  ear,  and  the  retrahent  muscle  of  the  pinna; 
and  the  other  supplies  the  hinder  belly  of  the  occipito-frontalis  muscle, 
and  the  integument  contiguous  to  it. 

LympatMcs.  Beneath  the  fascia  lies  a  collection  of  cervical  lymphatic 
glands  in  the  clavicular  part  of  the  posterior  triangle.  They  communi- 
cate below  with  the  lymphatics  of  the  axilla;  and  above  with  those  about 
the  ear  and  the  occiput,  by  means  of  the  superficial  lymphatic  vessels  and 
glands  accompanying  the  external  jugular  vein.  Beneath  the  sterno- 
mastoideus  they  join  also  the  deep  glands  by  the  side  of  the  carotid  ves- 
sels. 


DESCRIPTION  OF  PLATE  XVI. 

This  Plate  exhibits  a  surface-view  of  the  side  of  the  neck,  in  front 
of  a  line  from  the  mastoid  process  to  the  inner  end  of  the  clavicle. 

Supposing  the  skin  thrown  aside,  as  in  the  Figure,  the  thin  fleshy 
fibres  of  the  platysma  will  appear  through  a  slight  fatty  covering,  and 
may  be  readily  cleaned.  This  muscle  may  be  then  raised  towards  the 
jaw  by  a  cut  over  the  sterno-mastoideus,  the  superficial  veins  and  nerves 
being  traced  out  at  the  same  time.  Before  the  removal  of  the  deep 
fascia  the  subjacent  muscles  should  be  fixed  in  their  natural  position  by 
stitches,  to  prevent  their  slipping  out  of  place  when  the  investing 
sheaths  are  taken  away. 

Afterwards  the  areolar  tissue  and  fat  are  to  be  cleared  out  between 
the  jaw  and  the  hyoid  bone,  and  from  the  whole  surface  of  the  space 
laid  bare. 

SURFACE  VIEW  OF  THE  FRONT  OF  THE  NECK. 

The  prominent  sterno-mastoid  muscle,  B,  divides  into  two  the  side  of 
the  neck;  and  in  front  of  it  is  a  slight  hollow,  which  is  most  m^arked 
near  the  jaw,  and  is  wider  above  than  below. 

In  front  of  the  sterno-mastoideus  lie  the  elevator  and  depressor  mus- 


136  ILLUSTRATIONS    OF    DISSECTIONS. 

cles  of  the  hjoid  bone, — the  former  extending  downwards  from  the  lower 
jaw,  and  the  latter  reaching  upwards  from  the  chest  and  shoulder. 

Below  the  side  of  the  jaw  is  the  submaxillary  gland,  K,  with  a  chain 
of  small  lymphatic  glands  reaching  backwards  to  the  sterno-mastoid  mus- 
cle; and  a  lymphatic  gland,  with  a  small  artery  entering  it,  is  lodged  just 
above  the  body  of  the  liyoid  bone.  Between  the  jaw  and  the  ear  the 
parotid  gland,  L,  is  wedged  in. 

No  large  arterial  trunk  can  be  seen  on  the  surface  of  the  neck  as  long 
as  the  sterno-mastoideus  keeps  its  natural  position;*  and  this  Plate 
teaches  also  that  no  triangular  space  containing  the  large  cervical  blood- 
vessels is  observable  until  that  muscle  has  been  dis|)laced,  as  in  Plate 
jcviii. 

A  few  small  arteries  reach  the  surface.  Thus,  the  facial  artery,  a, 
T\ath  its  vein  winds  over  the  submaxillary  gland  and  the  jaw  in  frent  of 
the  masseter  muscle,  and  gives  forwards  the  submental  branch,  l,  below 
the  jaw;  whilst  opposite  the  back  of  the  liyoid  bone  the  lingual  A'essels, 
■c,  ajopear  for  a  short  distance.  Issuing  from  beneath  the  sterno-mastoi- 
deus are  small  cutaneous  offsets,  e,  of  the  upper  thyroid  artery — one,  d, 
'entering  the  superficial  lymphatic  gland  near  the  liyoid  bone;  and  pierc- 
ing the  sterno-mastoideus  are  other  cutaneous  arteries,  /,  of  the  subcla- 
vian and  external  carotid  trunks.  Near  the  ear  a  cutaneous  branch,  g, 
of  the  posterior  auricular  artery,  escaping  beneath  the  parotid  gland, 
«crosses-  over  the  sterno-mastoideus. 

Two  superficial  jugular  veins  are  directed  from  above  down  through 
the  anterior  part  of  the  neck.  One,  the  external  jugular,  li,  crosses  the 
sterno-mastoideus  from  before  back;  and  the  other,  the  anterior  jugular, 
I,  lies  in  front  of  that  muscle,  and  near  the  middle  line  of  the  neck. 

Cutaneous  nerves  cross  from  behind  forwards,  spreading  out  over  the 
Tegion  dissected.  The  nerve  marked,  1,  is  the  cervical  part  of  the  sev- 
■enth  cranial  nerve,  which  reaches  as  low  as  the  hyoid  bone;  and  the 
nerve,  2,  is  a  branch  of  the  cervical  plexus  to  the  teguments  below  the 
preceding. 


*  Anatomists  depict  and  describe  the  common  carotid  artery  as  uncovered  by 
tlie  sterno-mastoideus  at  its  upper  end.  And  the  directions  of  surgeons  for  plac- 
ing a  ligature  on  that  bloodvessel  are  based  on  the  same  inaccuracy. 


MUSCLES    AND    THE    CERVICAL    FASCIA. 


137 


jnJSCLES  AND  THE  CERVICAL  FASCIA. 

Most  of  the  muscles  laid  bare  will  be  described  more  fully  in  the 
explanation  of  the  following  Plate;  but  as  the  natural  state  of  the  sterno- 
mastoideus,  and  its  connection  with  the  cervical  fascia  would  be  destroyed 
by  tlie  deeper  dissection,  these  Avill  be  noticed  below. 


A.  Platysma  myoides,  cut. 

B.  Sterno-cleido-mastoideus. 

C.  Thyro-hyoideus. 

D.  Omo-hyoideus. 

E.  Sterno-hyoideus. 

F.  Anterior  belly  of  the  digastric 

muscle. 
H.  Stylo-hyoideus. 


J.  Hyoid  bone. 

K.  Submaxillary  gland. 

L.  Parotid  gland. 

N.  Process  of  the  deep  cervical  fas- 
cia fixing  the  sterno-mastoi- 
deus. 

t  Lymphatic  glands. 


The  stenio-cleido-mastoid  muscle,  B,  incases  somewhat  the  narrowed 
part  of  the  neck  by  the  elongation  of  its  edges  forwards  and  backwards. 
The  anterior  curved  border  is  manifest  in  the  Drawing,  and  it  is  kept  in 
this  position  by  a  piece  of  fascia,  N,  which  is  attached  to  the  lower  jaw. 

The  muscle  covers  the  carotid  bloodvessels  as  high  as  the  digastricus, 
and  even  when  the  head  is  thrown  backwards. 

In  tlie  operation  of  tying  the  common  carotid  artery  the  muscle  would 
have  to  be  dissected  back  for  some  distance  before  the  line  of  the  vessel 
is  reached;  and  pressure  on  the  artery  must  be  made  through  the  mus- 
cle. This  fleshy  covering  gives  protection  to  the  large  vessels:  and  these 
cannot  be  injured  in  Avounds  of  the  neck  unless  the  muscle  is  cut. 

Deep  cervical  fascia.  The  special  fascia  of  the  neck  invests  the 
muscles  with  sheaths.  Most  of  it  has  been  removed  in  cleaning  the  mus- 
cles; but  a  strong  process  marked,  N,  has  been  left  for  the  purpose  of 
showing  its  connection  on  the  one  hand  with  the  sterno-mastoideus,  and 
on  the  other  with  the  angle  of  the  lower  jaw.  The  office  of  this  piece  is 
to  keep  curved  the  anterior  border  of  the  sterno-mastoideus,  for  as  soon 
as  it  is  cut  the  edge  takes  a  straight  direction,  as  in  Plate  xvii. 


138  ILLUSTKATIOKS    OF    DISSECTIONS, 


CONNECTIONS  OF  THE  SALIVARY  GLANDS. 

On  each  side  there  are  three  salivary  glands  in  contact  with  the  lower 
Jaw.  One  is  lodged  behind  the  ramus  and  angle  of  the  bone,  and  is 
named  parotid:  another  is  partly  covered  by  the  side  of  the  jaw — the 
submaxillary;  and  the  third,  the  sublingual,  lies  beneath  the  front  of  the 
tongue. 

The  parotid  is  the  largest  of  the  salivary  glands.  It  is  placed  between 
the  jaw  in  front,  and  the  ear  with  the  mastoid  process  and  the  sterno- 
mastoideus  behind;  and  it  projects  downwards  beyond  the  level  of  the 
jaw,  where  the  process,  N,  of  the  cervical  fascia  separates  it  from  the 
submaxillary  gland. 

Towards  the  surface  the  gland  is  flat,  and  is  covered  by  the  deep  cer- 
vical fascia:  on  it  rest  one  or  more  lymphatic  glands.  Its  deep  part  is 
very  irregular  in  form,  and  sends  downwards  prolongations  around  the 
styloid  process. 

Several  vessels  and  nerves  pass  through  the  substance  of  the  parotid,  and 
the  position  of  these  may  be  studied  in  Plate  xvii.  The  external  carotid 
artery,  h,  ascends  through  the  gland  giving  off  the  auricular,  temporal, 
and  internal  maxillary  branches.  The  external  jugular  vein,  r,  begins 
by  the  union  of  the  temporal  and  internal  maxillary  branches,  and 
passes  downwards  superficially  to  the  carotid.  The  facial  nerve,  4,  tra- 
verses the  gland  from  behind  forwards,  over  the  artery,  and  is  joined  by 
offsets  of  the  great  auricular  nerve.  Close  to  the  ear  the  cutaneous  part, 
11,  of  the  auriculo-temporal  nerve  is  directed  upwards  by  the  side  of  the 
temporal  artery. 

The  excretory  duct  of  the  gland  (ductus  Stenonis)  leaves  the  fore  part, 
and  piercing  the  buccinator  muscle,  opens  into  the  mouth  opposite  the 
second  molar  tooth  of  the  upper  jaw  (Plate  xx.). 

In  enlargement  of  this  gland  the  swelling  will  project  downwards  at 
first  towards  the  deep  vessels  and  nerves  in  front  of  the  spine,  and  then 
into  the  neck  along  the  sterno-mastoideus;  but  extension  towards  the 
surface  will  be  delayed  by  the  strong  fascia  binding  it  down.  Much  pain 
will  attend  the  swelling  of  the  glands  in  "mumps"  and  other  affections, 


SUPERFICIAL    ARTERIES    OF    THE    NECK.  139 

just  as  111  all  inflamed  glundular  parts  that  are  prevented  expanding  by 
tlie  firmness  of  the  encasing  sheaths. 

The  swelling  and  abscesses  in  front  of  the  ear  in  scrofulous  children 
are  occasioned  by  inflammation  of  the  lymphatic  glands  on  the  surface  of 
the  parotid. 

The  suhmaxillary  gland,  K,  is  not  surrounded  by  such  unyielding 
structures  as  the  parotid;  for,  though  concealed  somewhat  by  the  side  of 
the  maxilla,  it  projects  down  the  neck  for  an  inch  or  more  in  front  of 
tlie  angle  of  the  jaw.  Superficial  to  it  are  the  integuments  and  the 
platysma  with  the  deep  fascia;  and  beneath  it  is  the  mylo-hyoid  mus- 
cle. In  front  it  is  bounded  by  the  anterior  belly  of  the  digastric,  F; 
below  by  the  digastric  and  the  stylo-hyoid,  H;  and  behind  by  the  process, 
N,  of  the  deep  cervical  fascia  which  intervenes  between  it  and  the  paro- 
tid.    Over  the  surface  wind  the  facial  vessels,  a. 

The  glands  consists  of  larger  lobules  than  the  parotid;  and  from  its 
deeper  surface  the  duct  (Wharton's)  is  continued  to  the  floor  of  the 
mouth:  the  course  of  the  duct  is  evident  in  Plate  xxii.  of  the  submaxillary 
region. 

The  sublingual  gland  jDrojects  in  the  floor  of  the  mouth  under  the 
front  of  the  tongue,  where  it  forms  a  lengthened  swelling.  Placed  deeply 
under  the  side  of  the  jaw,  close  to  the  symphysis,  its  connections  will  be 
indicated  in  Plate  xxii. 

The  lymi)hatic  glands  marked  thus,  f ,  are  three  or  four  in  number, 
and  lie  along  the  base  of  the  jaw,  superficial  to  the  submaxillary  gland: 
they  receive  vessels  from  the  submental  artery,  h.  In  scrofulous  children 
these  glands  may  enlarge,  and  suppurate. 

In  the  middle  line,  just  above  the  hyoid  bone,  is  a  small  lymphatic 
gland,  which  receives  a  vessel,  d,  from  the  upper  thyroid  artery. 


SUPERFICIAL  ARTERIES  OF  THE  NECK. 

In  comparison  with  the  superficial  veins  the  arteries  appearing  on  the 
surface  are  few,  and  are  small  in  size.  None  except  the  facial,  a,  and 
the  lingual,  c,  are  large  enough  to  furnish  serious  haemorrhage  in  sujjer- 
ficial  wounds;  but  in  cuts  involving  the  muscles,  the  large  trunks  displayed 
in  Plate  xvii.  may  be  opened. 


140  ILLUSTRATIONS    OF    DISSECTIONS. 


a.  Facial  artery  and  vein. 

b.  Submental  branch  of  the  facial. 

c.  Lingual  artery  and  veins. 

d.  Offset  of  the  upper  thyroid  artery 

to  a  lymphatic  gland. 


ee.  Superficial  offsets  of  the  upper 

thyroid  artery. 
ff.  Branches  of  the  subclavian  and 

carotid  trunks  i^erforating  the 

sterno  •  mastoideus. 
g.  Cutaneous  offset  of  the  posterior 

auricular. 


The  anatomy  of  the  several  arteries  will  be  giren  with  the  description 
of  Plate  xyii. 


SUPERFICIAL  VEINS  OF  THE  NECK.  ' 

Two  superficial  jugular  veins,  and  the  facial  and  Unguals  veins,  appear 
in  this  dissection. 


h.  External  jugular  vein. 
I.  Anterior  jugular  vein. 


71.  Facial  vein. 


The  external  jugular  vein,  h,  is  figured  in  the  part  of  its  course  which 
is  superficial  to  the  deep  fascia  of  the  neck,  and  is  concealed  by  the  pla- 
tysma  muscle,  A  (p.  131). 

The  anterior  jugular  vein,  /,  begins  in  the  teguments  below  the  chin, 
and  communicates  with  a  branch  of  the  facial  vein.  Lying  superficially 
near  the  anterior  edge  of  the  sterno-mastoideus,  it  sinks  through  the 
cervical  fascia,  near  the  sternum,  and  opens  into  the  subclavian  vein 
(Plate  xviiL).  It  unites  commonly  by  a  branch  with  the  external  jugu- 
lar. 

CUTANEOUS  NERVES  OF  THE  FRONT  OF  THE  NECK. 

The  facial  nerve  and  branches  of  the  cervical  plexus  supply  the  super- 
ficial structures  of  the  neck. 


1.  Cervical  part  of  the  facial  nerve. 

2.  Superficial  cervical  nerve. 


8.  Great  auricular  nerve. 


The  infra-maxillary  branch,  1,  of  the  facial  nerve,  issuing  from  be- 
neath the  parotid,  sends  forwards  offsets  beneath  the  platysma  as  low  as 
the  hyoid  bone:  it  supplies  that  muscle  and  the  integuments. 


PLATE  XVIi 


H.Bvuck*.  Lit» 


i 


ANTERIOR    TRIANGULAR    SPACE.  14:1 

The  snpei'iicial  cervical  nerve,  2,  is  bent  forwards  under  the  phitysma, 
and  its  branches  pierce  the  muscle  to  supply  the  integuments  between 
the  hyoid  bone  and  the  sternum.  AboYC,  it  joins  the  facial  nerve:  and 
it  is  said  to  give  offsets  to  the  lower  part  of  the  platysma. 

The  r/renf  anricvJar  nerve,  3,  ascends  by  the  side  of  the  external  jugu- 
lar vein  to  the  ear,  and  ends  as  before  said  (p.  133). 


DESCRIPTION  OF  PLATE  XVII. 


The  anterior  triangular  space  of  the  neck,  as  it  appears  after  displace- 
ment of  the  sterno-mastoid  muscle,  is  shown  in  this  Figure. 

Whilst  the  skin  is  being  reflected  forwards,  the  platysma  muscle  may 
be  denuded;  and  this  muscle  and  the  deep  cervical  fascia  should  be  then 
raised.  Afterwards  the  parotid  gland  is  to  be  picked  out  of  the  hollow 
between  the  ear  and  the  jaw,  and  the  areolar  tissue  and  the  fat  are  to  be 
removed  from  the  space,  as  is  seen  in  the  Drawing,  without  injury  to 
the  numerous  vessels  and  nerves. 


ANTERIOR  TRIANGULAR  SPACE. 

This  intermuscular  space  corresponds  with  the  surface-depression  be- 
tween the  jaw  and  the  sternum,  and  contains  the  carotid  bloodvessels  with 
their  companion  veins  and  nerves,  and  some  salivary  and  lymphatic 
glands. 

Triangular  in  form,  with  the  base  upwards,  it  is  bounded  in  the  fol- 
lowing way.  Behind  is  the  reflected  stcrno-mastoideus  with  the  ear;  and 
in  front  the  space  reaches  to  the  middle  lino  of  the  neck.  At  the  base  lies 
a  jaw-bone;  and  the  apex  touches  the  top  of  the  sternum. 

Stretched  over  the  hollow  are  the  teguments,  with  the  platysma  mus- 
cle and  the  deep  cervical  fascia;  and  in  the  floor  the  air  and  food  passages 
are  lodged,  covered  by  the  muscles  of  deglutition. 

The  depth  increases  from  below  upwards;  and  it  is  greatest  along  the 
upper  two  thirds  of  the  sterno-mastoideus  and  the  front  of  the  ear,  where 


142  ILLUSTRATIONS    OF    DISSECTIONS. 

the  great  vessels  and  nerves  are  placed,  but  it  diminishes  gradually  to- 
wards the  front. 

Along  the  middle  of  the  neck  lie  certain  well-marked  prominences, 
which  can  be  felt  readily  by  the  finger  during  life,  and  serve  as  guides  in 
in  operations  on  the  vessels  and  the  windpipe.  About  two  inches  from 
the  lower  Jaw,  when  this  is  raised,  projects  the  narrow  firm  line  of  the 
hyoid  bone,  which  is  marked  J,  in  the  preceding  Plate.  A  finger's 
breadth  below  that  bone  the  prominence  of  the  thyroid  cartilage  of  the 
larynx  (pomum  Adami)  is  met  with.  Still  lower,  about  an  half  an  inch, 
comes  the  firm  cricoid  or  ring  cartilage  of  the  larynx, — a  prominence 
less  than  the  former;  and  between  the  two  is  a  slight  hollow,  opposite 
the  crico-th}Toid  membrane,  through  which  the  knife  is  sunk  in  the 
operation  of  laryngotomy.  From  this  point  to  the  sternum  the  tube  of 
the  windpipe  and  the  thyroid  body  carry  forwards  the  muscles:  the  former 
can  be  recognized  by  the  finger. 

Behind  the  os  hyoides  and  the  larynx  and  trachea  lies  the  pharynx 
with  the  oesophagus. 

Position  of  arteries.  Opposite  the  level  of  the  cricoid  cartilage  the 
large  trunk  of  the  common  carotid,  a,  escapes  from  beneath  the  depressor 
muscles  of  the  hyoid  bone.  In  company  with  the  internal  jugular  vein 
it  lies  between  the  pharynx  and  the  spine,  and  ascends  under  cover  of  the 
sterno-mastoideus.  A,  to  the  upper  border  of  the  thyroid  cartilage,  where 
it  splits  into  the  external  carotid,  h,  and  internal  carotid,  c.  From  the 
jioint  of  division  these  two  arteries  are  continued  in  the  direction  of  the 
parent  trunk  to  the  interval  between  the  ear  and  the  jaw,  and  they  end 
in  the  following  way: — one  (external)  is  consumed  in  offsets  outside 
the  cavity  of  the  skull;  and  the  other  (internal)  is  distributed  chiefly  to 
the  brain,  without  furnishing  branches  to  the  neck.  Neither  vessel  is 
visible  till  after  the  sterno-mastoideus  has  been  displaced.  See  Plate 
xvi. 

Position  of  veins.  By  the  side  of  the  common  carotid  artery  is  the 
internal  jugular  vein,  j9;  and  it  is  continued  to  the  base  of  the  skull  along 
the  internal  carotid  trunk.  In  the  upper  narrowed  part  of  the  space  be- 
tween the  jaw  and  the  ear  the  external  jugular  vein  begins;  but  it  then 
runs  downwards  over  the  sterno-mastoideus.  Near  the  middle  line  of  the 
neck  the  anterior  jugular  vein,  s,  descends  (Plate  xvi.);  and  it  passes  be- 
neath the  sterno-mastoideus  at  the  lower  part  of  the  neck. 

Position  of  nerves.     Many  nerve  trunks  lie  in  contact  with  the  great 


MUSCLES  OF  THE  FRONT  OF  THE  NECK. 


143 


bloodvessels,  and  most  of  them  accompany  those  vessels  to  the  base  of  the 
skull. 

Superfical  to  the  sheath  of  the  vessels  where  the  common  carotid  may 
be  tied,  is  the  descendens  noni  nerve,  3.  A  little  above  the  hyoid  bone 
the  hypoglossal  nerve,  14,  is  directed  forwards  over  both  carotid  arteries; 
and  in  front  of  the  ear  the  branches  of  the  facial  nerve,  4,  cross  over  the 
external  carotid. 

On  a  line  with  the  base  of  the  jaw-bone  the  glosso-i^haryngeal  nerve 
is  inclined  inwards  between  both  arteries. 

In  the  sheath,  between  and  parallel  with  the  vein  and  artery,  the 
vagus  nerve  extends  through  the  neck  (Plate  xxiv.);  two  of  its  branches, 
the  superior  laryngeal,  1,  and  the  external  laryngeal,  2,  being  directed 
inwards  to  the  larynx. 

Beneath  the  sheath  the  cord  of  the  sympathetic  nerve  (Plate  xxiv. ) 
rests  on  the  spinal  column. 

External  or  posterior  to  the  sheath  for  a  short  distance  is  the  spinal 
rxcessory  nerve,  13,  as  this  issues  from  beneath  the  digastric  muscle,  K. 

One  small  nerve  is  altogether  removed  from  the  sheath:  it  is  the  mylo- 
hyoid branch,  12,  of  the  inferior  maxillary  nerve  (Plate  xxi.),  and  escapes 
from  under  the  jaw-bone. 

Glands  of  the  space.  Two  large  salivary  glands,  the  parotid  and  sub- 
maxillary, which  are  seen  in  Plate  xvi.,  Avhere  they  are  marked  L  and  E, 
occupy  the  base  of  the  triangular  space. 

The  lymphatic  glands  have  been  cleared  away  in  the  dissection:  one 
set  lies  along  the  jaw-bone  (Plate  xvi.);  and  the  other  (deep  cervical)  is 
placed  along  the  side  of  the  jugular  vein,  under  the  sterno-mastoideus. 


MUSCLES  OF  THE  FRONT  OF  THE  NECK. 


The  muscles  occupying  the  upper  and  fore  parts  of  the  triangular  space 
converge  to  the  os  hyoides — the  upper  set  elevating,  and  the  lower  set 
depressing  that  bone. 


A.  Sterno-mastoideus. 

B.  Stylo-hyoideus. 

C.  Omo-liyoideus — anterior  belly. 

D.  Sterno-tliyroideus. 
F.  Thyro-hyoideus. 


H,  Digastricus — anterior  belly, 

N.  Hyo-glossus. 

P.    Stylo-hyoideus. 

R.  Digastricus — posterior  belly. 

S.  Masseter. 


144  ILLUSTRATIONS    OF    DISSECTIONS. 

■  Depressors  of  the  os  hyoides.     These  muscles  cover  the  trachea  and 
larynx,  and  are  marked  B,  C,  and  J). 

Omo-hyoideus,  C.  The  anterior  belly  of  this  muscle  crosses  the  com- 
mon carotid  artery  and  jugular  yein  just  below  the  cricoid  cartilage,  and 
is  inserted  into  the  body  of  the  hyoid  bone  close  to  the  great  cornu.  For 
the  posterior  belly,  see  Plate  xv.  and  page  123. 

Sterno-hyoideus,  B.  The  muscle  arises  from  the  inner  surface  of  the 
sternum  and  first  rib,  and  is  inserted  mto  the  middle  of  the  body  of  the 
hyoid  bone. 

Sterno-thyroideus,  D,  arises  lower  in  the  chest  than  the  preceding, 
though  like  it  from  the  sternum  and  the  rib,  and  is  inserted  into  the 
oblique  line  on  the  thyroid  cartilage,  where  it  is  continuous  with  the  fol- 
lowing. 

The  small  thyro-liyoideus,  F,  joining  the  preceding  below,  is  inserted 
into  the  anterior  half  of  the  great  cornu,  and  into  part  of  the  body  of 
the  OS  hyoides. 

This  group  of  muscles  is  covered  partly  by  the  sterno-mastoideus;  and 
it  conceals  the  windpipe  and  the  thyroid  body,  and  the  sheath  of  the 
great  bloodvessels.  An  interval  separates  the  muscles  of  opposite  sides 
along  the  middle  line  of  the  neck,  except  for  about  an  inch  above  the 
sternum,  where  the  sterno-thyroid  muscles  touch. 

Action.  Commonly  the  muscles  act  from  the  sternum,  and  draw 
down  rapidly  the  os  hyoides  as  soon  as  the  morsel  of  food  or  the  fluid  to 
be  swallowed  has  passed  the  upper  aperture  of  the  larynx.  If  they  take 
their  fixed  point  above,  the  sterno-hyoid  and  the  sterno-thyroid  will  assist 
in  dilating  the  chest  in  laborious  breathing;  and  the  small  thyro-hyoid, 
F,  will  raise  and  tilt  backwards  the  thyroid  cartilage — relaxing  thereby 
the  vocal  cords. 

Elevators  of  the  hyoid  hone.  These  muscles  are  more  numerous  than 
their  antagonists,  for  some  extrinsic  muscles  of  the  tongue  help  to  raise  the 
OS  hyoides:  the  deeper  muscles  of  the  set  maybe  referred  to  in  Plate  xxii. 

Stylo-hyoideus,  P.  Arising  near  the  root  of  the  styloid  process,  the 
muscle  is  divided  into  two  parts,  between  which  passes  the  tendon  of  the 
posterior  belly,  E,  of  the  digastricus;  and  it  is  inserted  into  the  body 
or  the  great  cornu  of  the  os  hyoides,  joining  the  aponeurosis  of  the  di- 
gastricus. 

The  digastric  muscle  consists  of  two  fleshy  parts  with  an  intermediate 
tendon. 


ELEVATOR    MUSCLES    OF   THE    OS    HY0IDE8.  145 

The  posterior  belly,  K,  is  fixed  to  the  groove  beneath  the  mastoid  pro- 
cess of  the  temporal  bone;  and  the  anterior,  H,  is  attached  to  the  jaw 
close  to  the  symphysis.  Below,  the  muscle  is  connected  to  the  surface  of 
thebodyof  the  liyoid  bone  by  a  thin  aponeurosis,  which  joins  the  anterior 
belly  and  the  fore  part  of  the  tendon.* 

The  digastric  incloses  with  the  jaw  a  space  in  which  the  two  superficial 
salivary  glands  are  lodged.  And  the  posterior  belly  marks  the  spot  at 
Avhich  the  carotid  bloodvessels  become  deep  and  inaccessible;  the  position 
of  this  part  of  the  muscle  corresponds  with  a  line  on  the  surface  from  the 
mastoid  process  to  a  point  half  an  inch  above  the  hyoid  bone. 

The  mylo-hyoid  muscle  descends  from  the  jaw-bone  to  the  body  of  the 
OS  hyoides:itlics  beneath  the  anterior  belly  of  the  digastric,  and  in  Plate 
xxii.,  where  it  is  reflected,  it  may  be  seen  to  join  its  fellow  along  the 
middle  line  of  the  neck. 

The  geniO'hyoideus  is  beneath  the  preceding.  Plate  xxii.  shows  it  in 
position,  reaching  from  the  jaw  to  the  hyoid  bone. 

Two  tongue  muscles — hyo  and  genio-glossus — may  act  as  elevators  of 
the  hyoid  bone:  the  hyo-glossus  is  marked  with  N  in  the  Figure,  and  both 
are  displayed  fully  in  Plate  xxii. 

Action  of  the  elevators.  With  the  mouth  shut  and  the  tongue  fixed 
against  the  roof,  the  muscles  will  assist  in  preparing  the  pharynx  for  the 
reception  of  the  food,  by  drawing  upwards  and  forwards  the  os  hyoides, 
so  as  to  bring  the  larynx  under  shelter  of  the  tongue.  But  if  the  mouth 
is  open  and  the  tongue  not  in  contact  with  the  roof,  the  muscles  are  de- 
prived of  their  usual  point  of  support  above,  and  swallowing  will  be  per- 
formed Avith  difficulty ; — the  necessary  elevation  of  the  hyoid  bone  in 
this  imperfect  deglutition  being  then  dependent  upon  the  stylo-hyoideus 
and  posterior  belly  of  the  digastricus,  which  retain  their  usual  position, 
and  on  the  extreme  contraction  of  the  other  muscles. 

Supposing  the  os  hyoides  fixed  by  its  depressors,  the  muscles  used 
commonly  as  elevators  of  that  bone  will  have  a  different  action: — those 
attached  to  the  jaw  may  then  carry  it  downwards,  so  as  to  open  the  mouth; 
and  the  lingual  muscles  can  depress  the  tongue. 

*  There  are  great  variations  with  respect  to  this  attachment  and  the  state  of  the 
stylo-hyoideus  muscle:  some  of  these  may  be  perceived  in  the  different  Plates. 


10 


146  ILLUSTRATIONS   OF    DISSECTIONS. 


ARTERIES  OF  THE  FRONT  OF  THE  NEC-K. 

Only  the  carotid  trunks  and  some  branches  of  the  external  carotid 
artery  are  visible  in  front  of  the  sterno-mastoideus. 


a.  Common  carotid  artery. 
h.  External  carotid  artery. 
c.  Internal  carotid  artery. 
cl.  Superior  tliyroid  artery. 
e.  Lingual  artery. 
/.  Facial  artery. 


g.  Occipital  artery. 
h.  Posterior  auricular  artery. 
I.  Superficial  temporal  artery. 
n.  Internal  maxillary  artery. 
X  Spot  for  ligature  of  the  common 
carotid  artery. 


The  common  carotid  trunk,  a,  begins  opposite  the  sterno-clavicular 
articulation,  and  ends  at  the  upper  edge  of  the  thyroid  cartilage  by  split- 
ting into  two — external  and  internal  carotid.  Its  situation  will  be  marked 
on  the  surface  by  a  line  from  the  inner  end  of  the  clavicle  to  a  point  mid- 
way between  the  jaw  and  the  ear. 

Contained  in  a  sheath  of  fascia  with  the  jugular  vein  and  the  vagus 
nerve,  it  is  covered  throughout  by  muscles;  and  it  has  the  following 
connections  with  the  contiguous  parts: — Superficial  to  it,  besides  the 
teguments  and  the  platysma,  are  the  depressors  of  the  hyoid  bone  and  the 
sterno-mastoideus — the  last  muscle  covering  it  to  the  ending  (Plate  xvi.); 
and  the  others,  only  as  high  as  the  cricoid  cartilage.  Beneath  the  vessel 
is  the  spinal  column.  To  its  inner  side  lie  the  gullet  and  the  air  passage, 
with  the  thyroid  body;  and  as  the  trachea  swells  out  to  form  the  larynx, 
necessarily  the  artery  is  carried  farther  from  its  fellow  above  than  be- 
low. Along  the  outer  side  is  a  chain  of  lymphatic  glands,  which  is 
liable  to  become  enlarged. 

The  internal  jugular  vein,  p,  is  parallel  to,  and  in  close  contact  exter- 
nally with  the  artery;  and  on  the  left  side  the  vein  advances  over  it, 
especially  lower  in  the  neck.  Three  veins  cross  the  artery; — near  the 
chest  is  the  anterior  jugular  vein,  s;  near  the  ending  the  upper  thyroid 
vein;  and  below,  X,  the  middle  thyroid  vein. 

In  front  of  the  sheath,  in  the  upper  half,  the  descendens  noni  nerve, 
3,  crosses  obliquely  from  without  inwards.  Beneath  tlie  sheath  is  the 
sympathetic  nerve;  and  lower  down  the  recurrent  laryngeal  nerve  and 


LIGATURE    OF    THE    CAROTID    ARTERY.  147 

inferior  thyroid  artery  cross  inwards  under  it.     In  the  sheath,  between 
the  artery  and  vein  l^os  the  vagus  nerve. 

No  collateral  offset  arises  commonly  from  the  carotid  artery,  and  the 
trunk  remains  nearly  of  the  same  size;  but  not  nnfrequently  the  upper 
thyroid  branch  d  is  transferred  to  the  slight  dilatation  at  the  end. 

Ligature  of  the  vessel.  Tlic  part  of  the  common  carotid  marked  thus 
X  is  selected  for  ligature  because  it  is  far  removed  from  each  end,  and 
because  it  is  less  deep  here  than  at  a  lower  point.  But  since  the  vessel 
may  bifurcate  as  low  as  the  cricoid  cartilage  or  even  lower,  two  trunks 
instead  of  one  may  be  met  with  at  this  spot.  Should  the  point  of  split- 
ting of  the  artery  be  recognized  in  the  operation  of  ligature  both  trunks 
may  be  tied;  but  if  the  origin  of  the  two  trunks  cannot  be  seen  in  conse- 
quence of  the  artery  having  divided  very  soon,  the  finger  may  be  pressed 
on  each,  and  that  trunk  may  be  tied  which  takes  blood  to  the  disease  or 
injury  for  which  the  operation  was  undertaken  (Quain). 

Steps  of  the  operation.  With  the  line  of  the  vessel  in  mind,  the 
operator  places  the  forefinger  of  the  left  hand  opposite  the  cricoid  carti- 
lage, and  makes  an  incision  in  that  line  three  inches  in  length  (the  finger 
marking  the  centre)  through  the  integuments,  platysma,  and  deep  fascia, 
down  to  the  fibres  of  the  sterno-mastoideus:  should  the  cut  be  made  too 
far  forwards,  the  anterior  jugular  vein  may  be  injured.  Next  the  sterno- 
mastoid  muscle  is  to  be  dissected  back  rather  beyond  the  position  of  the 
arter}-,  the  head  being  inclined  towards  the  shoulder  of  the  same  side  to 
relax  its  fibres.  The  operator  now  looks  for  the  deep  guide,  viz.,  the 
angle  formed  below  by  the  omo-hyoid  muscle,  C,  and  the  sterno-mastoid- 
eus, A,  and  seeks  the  vessel  at  that  spot,  dissecting  but  very  little,  because 
the  descendens  noni  nerve,  3,  and  offsets  of  the  upper  thyroid  vessels  to 
the  sterno-mastoideus  cross  tlic  sheath. 

The  sheath  is  next  to  be  ojDencd  towards  the  inner  part — over  the  ar- 
tery— avoiding  the  nerve,  and  the  small  vessels  if  possible;  and  after  the 
artery  has  been  separated  from  its  sheath  the  needle  is  to  be  passed  under 
it,  whilst  the  opposite  side  of  the  sheath  is  raised  with  a  pair  of  forceps. 
Between  the  artery  and  vein  lies  the  vagus  nerve:  this  is  not  to  be  in- 
cluded in  the  ligature,  and  if  the  artery  has  been  carefully  detached  the 
nerve  cannot  well  be  caught.  Before  tying  the  thread  the  operator  should 
ascertain  that  the  pulsation  in  the  vessel  can  be  stopped  by  pressure. 

Should  the  artery  be  denuded  too  much,  the  application  of  two  liga- 
tures may  be  needful — one  at  each  end  of  the  part  laid  bare.     And  should 


148  ILLUSTRATIONS    OF    DISSECTIONS. 

the  size  of  the  vein  be  inconveniently  large,  i  t  may  be  diminished  by  the 
pressure  of  the  finger  of  an  assistant  at  the  upper  part  of  the  wound. 

In  an  operation  on  the  left  side  the  vein,  from  its  position  over  the 
artery,  would  have  to  be  turned  aside;  and  this  step  may  be  needed  also 
on  the  right  side  when  the  vein  covers  the  artery. 

In  the  operation  on  the  dead  body  the  needle  will  pierce  readily  the 
coats  cf  a  large  loose  artery,  if  force  is  used;  and  any  check  therefore  to 
the  progress  of  the  needle  in  the  living  body  should  be  met  by  drawing 
back  the  point  of  the  instrument,  and  by  pulling  upwards  tightly  with  a 
forceps  the  opposite  side  of  the  sheath  before  another  attempt  is  made  to 
pass  the  ligature. 

The  internal  carotid  artery,  c,  is  the  direct  continuation  of  the  com- 
mon carotid  trunk,  and  enters  the  skull  through  the  temporal  bone 
(Plate  xxiv.).  Below  the  level  of  the  digastric  muscle  the  artery  may  be 
reached  by  the  surgeon,  but  above  that  muscle  it  is  quite  inaccessible. 
No  offset  is  given  from  this  vessel  in  the  neck. 

In  the  accessible  part  of  its  course  it  corresponds  with  the  surface-line 
of  the  common  carotid.  It  is  covered,  like  that  vessel,  by  the  sterno- 
mastoideus,  and  rests  on  the  spine; — at  this  spot  it  lies  external  or  pos- 
terior to  the  external  carotid  trunk.  The  internal  jugular  vein,  and  the 
vagus  and  symioathctic  nerves,  have  the  same  position  to  the  internal,  as 
to  the  common  carotid  artery. 

Crossing  the  artery  superficially  is  the  hypoglossal  nerve,  14,  which 
sends  down  the  descendens  noni  branch,  3;  and  beneath  it  the  superior 
laryngeal  nerve,  1,  is  directed  inwards.  The  occipital  artery,  g,  runs 
backwards  over  it,  commonly  near  the  digastric  muscle,  but  sometimes 
lower  down  as  in  the  Figure:  a  branch  of  this, supplies  the  sterno-mas- 
toideus. 

Ligature.  If  this  artery  is  ever  tied  it  should  be  secured  as  far  from 
its  origin  as  it  well  can  be;  and  a  point  between  the  hyoid  bone  and  the 
digastric  muscle  may  be  selected  as  the  most  suitable.  But  the  joart  of 
the  artery  available  may  be  very  short  in  consequence  of  the  common 
carotid  ascending  as  far  as,  or  farther  than  the  os  hyoides  before  it  splits. 
Should  the  forked  ending  of  the  common  trunk  be  found  in  an  operation, 
both  the  resulting  arteries  may  be  secured  at  their  origin.  Occasionally 
the  ending  of  the  common  carotid  rises  still  nearer  to  the  head,  and  in 
those  cases  no  part  of  the  internal  carotid  will  be  below  the  digastric 
muscle. 


LIGATUKE    OF    THE    EXTERNAL    CAROTID.  149 

The  spot  for  the  application  of  the  ligature  being  well  ascertained  hj 
means  of  the  digastric  muscle,  the  hyoid  bone,  and  the  line  of  the  artery, 
the  first  stops  of  the  operation,  and  the  parts  to  be  cut  through  are  the 
same  as  those  before  given  for  ligature  of  the  common  carotid.  After 
the  sterno-mastoid  muscle  has  been  reflected  the  hypoglossal  nerve  and 
the  occipital  artery,  with  their  branches,  may  be  met  with.  When  laying 
bare  the  artery  care  must  be  taken  of  the  external  carotid  trunk  on  the 
one  side,  and  of  the  internal  jugular  vein  on  the  other;  and  in  passing 
the  aneurism  needle  the  same  precautions  are  to  be  observed  as  in  the  case 
of  the  common  carotid  (p.  147). 

The  external  carotid  artery,  l,  reaches  from  the  upper  border  of  the 
thyroid  cartilage  nearly  to  the  neck  of  the  lower  jaw,  and  ends  by  divid- 
ing into  temporal  and  maxillary  branches.  It  is  smaller  than  the  internal 
carotid;  and  it  distributes  branches  to  the  neck,  and  the  outer  parts  of 
the  head.  At  first  it  is  placed  on  the  anterior  or  inner  side  of  the  in- 
ternal carotid,  but  afterwards  becomes  superficial  to  that  vessel. 

As  high  as  the  mastoid  process  the  artery  is  covered  by  the  sterno- 
mastoideus,  A,  the  digastricus,  E,  and  the  stylo-hyoideus,  P,  besides  the 
common  investing  superficial  layers;  and  thence  to  its  ending  it  is  con- 
cealed by  the  parotid  gland  (Plate  xvi.).  Anterior  to  it  are  the  pharynx 
and  the  jaAv;  and  beneath  it  is  the  styloid  process.  No  companion  vein 
belongs  to  this  artery. 

Several  nerves  cross  this  carotid  trunk: — superficial  to  it  near  the  be- 
ginning is  the  hypoglossal  nerve,  14,  and  near  the  ending  the  ramifications 
of  the  facial  nerve,  4;  whilst  beneath  it  lie  the  external  laryngeal,  2,  the 
superior  laryngeal,  1,  and  near  the  jaw  the  glosso-pharyngeal  (Plate 
xxii.). 

The  offsets  of  the  artery  are  numerus: — they  consist  of  an  anterior  set 
of  three,  viz.,  thyroid,  cl,  lingual,  e,  and  facial,/;  a  posterior  set  of  two, 
occipital,  g,  and  posterior  auricular,  h;  and  an  ascending  set,  also  three 
in  number,  the  temporal,  /,  internal  maxillary,  n,  and  ascending  pharyn- 
geal (Plate  xxiv.). 

Ligature.  The  artery  is  accessible  below  the  digastric  muscle,  and  here 
it  is  covered,  like  the  internal  carotid,  by  the  sterno-mastoideus.  Its 
branches  are  attached  to  the  trunk  so  thickly  as  not  to  leave  space  enough 
between  any  two  for  the  application  of  a  ligature  without  the  prospect  of 
hemorrhage  when  the  thread  comes  away.  Before  the  removal  of  tumors 
about  the  jaw,  ligature  of  the  external  carotid  trunk  might  be  considered 


150  ILLUSTRATIONS    OF   DISSECTIONS. 

advisable  as  an  auxiliary  means  of  checking  liEemorrhage  during  an  opera- 
tion. 

In  a  wound  of  a  branch  of  the  external  carotid  the  vessel  should  be 
tied,  as  a  rule,  where  it  is  injured;  but  in  hfemorrhage  from  the  artery 
of  the  tongue,  where  the  bleeding  orifice  cannot  be  secured,  the  surgeon 
may  have  recourse  to  ligature  of  the  artery  nearer  the  origin  from  the 
common  trunk. 

Branches  of  the  carotid.  The  upper  thyroid,  d,  ends  in  the  thyroid 
body:  it  gives  offsets  to  the  contiguous  muscles,  and  a  laryngeal  branch 
to  the  interior  of  the  larynx  with  the  upper  laryngeal  nerve,  1. 

The  lingual  artery,  /,  is  distributed  to  the  tongue.     Arising  above  or 
below  the  cornu  of  the  hyoid  bone  it  is  directed  inwards  beneath  the  hyo- 
^glossus  muscle,  N.     In  the  tongue  the  arteries  of  opposite  sides  converge 
to  the  tip  (Plate  xxii.). 

If  this  artery  is  to  be  tied  it  may  be  secured  between  the  origin  and 
the  edge  of  the  hyo-glossus  muscle,  as  it  passes  near  the  cornu  of  the 
hyoid  bone.  An  incision  directed  downwards  and  backwards  over  the 
cornu  of  the  os  hyoicles  would  allow  the  artery  to  be  laid  bare:  the  hypo- 
glossal nerve  is  a  valuable  guide  to  the  position  of  the  vessel  in  the  bottom 
of  the  wound. 

The  facial  artery,/,  comes  off  near  the  digastricus,  and  courses  under 
it  and  the  stylo-hyoideus,  but  over  the  submaxillary  gland.  It  supplies 
branches  to  the  surrounding  parts,  and  a  submental  ofEcct  below  the  jaw. 

As  it  crosses  the  jaw  it  lies  in  front  of  the  masseter,  Avhere  it  is  cov- 
ered by  the  platysma:  it  can  be  easily  compressed  with  the  finger  in  that 
situation. 

The  occipital  artery,  g,  begins  near  the  digastric  muscle,  and  is 
directed  beneath  it  to  the  occiput:  the  hypoglossal  nerve  hooks  round  the 
vessel  when  this  arises  low  down.  One  or  more  offsets  enter  the  sterno- 
mastoideous. 

The  posterior  auricular,  h,  springs  near  the  upper  border  of  the  digas- 
tricus, and  runs  to  the  back  of  the  ear.  A  cutaneous  offset  passes  to  the 
occiput. 

Temporal  and  internal  maxillary.  The  maxillary,  n,  courses  beneath 
the  jaw;  and  it  will  be  met  with  in  other  dissections.  The  temporal,  /, 
ascends  to  the  side  of  the  head,  and  gives  offsets  to  the  ear:  anteriorly  it 
supplies  a  large  branch  to  the  face — transverse  facial. 


NERVES  OF  THE  FRONT  OF  THE  NECK. 


151 


VEINS  OF  THE  FRONT  OF  THE  NECK. 

Three  in  number,  the  veins  are  named  jugular — internal,  external, 
and  anterior;  and  they  return  to  the  chest  the  blood  circulated  through 
the  head  and  neck  by  the  carotid  arteries. 


p.  Internal  jugular  vein. 
r.  External  jugular  vein. 


s.  Anterior  jugular  vein. 


The  inteQmal  jugular  vein,  j??,  reaches  from  the  foramen  jugulare  in 
the  base  of  the  skull  to  the  inner  end  of  the  clavicle,  where  it  joins  the 
subclavian  vein  (Plate  xviii.).  In  the  neck  it  is  the  companion  vein  to 
the  common,  and  the  internal  carotid  artery;  and  it  is  joined  by  the 
A"eins  corresponding  with  the  branches  of  the  external  carotid,  with  the 
exception  of  three  which  enter  the  external  jugular. 

External  jugular,  r.  The  course  and  ending  of  this  vein  have  been 
before  described  (p.  131).  In  the  Drawing  the  beginning  of  the  veins  by 
the  union  of  the  temporal  and  internal  maxillary  may  be  perceived:  into 
the  vein  the  posterior  auricular  branch  is  received  lower  down. 


NERVES  OF  THE  FRONT  OF  THE  NECK. 

Several  cranial  nerves  appear  in  the  region  dissected;  and  they  are 
distributed  to  the  face,  the  tongue,  the  windpipe,  and  the  gullet.  Only 
one  spinal  nerve  is  seen. 


1.  Upper  laryngeal  nerve. 

2.  External  laryngeal  nerve. 

3.  Descendens  noni  nerve. 

4.  Facial  nerve. 

5.  Temporo-facial  piece  of  the  facial 

nerve. 

6.  Cervico-facial  piece  of  the  facial 

nerve. 

7.  Nerve  to  the  digastric  and  stylo- 

hyoid muscles. 


8.  Posterior  auricular  nerve. 

9.  Branches  of  the  great  auricular 

nerve  joining  the  facial. 

10.  Great  auricular  nerve. 

11.  Auriculo-temporal  branch  of  the 

fifth  nei-ve. 

12.  Mylo-hyoid   branch   of  the  fifth 

nerve. 
IS.  Spinal  accessory  nerve. 
14.  Hypoglossal  nerve. 


The  facial  nerve,  4,  issuing  from  the  skull  by  the  stylo-mastoid  f  ora- 


152  ILLUSTRATIONS    OF    DISSECTIONS. 

men,  divides  into  two  cliief  parts, — temporo-facial,  5,  and  cervico-facial, 
6:  these  pass  forwards  through,  the  j)arotid  gland  to  the  forehead,  the 
face,  and  the  superficial  parts  of  the  neck  as  low  as  the  hyoid  bone. 

As  soon  as  the  nerve 'leaves  its  bony  canal  it  gives  off  the  posterior 
auricular  nerve,  8,  and  a  muscular  branch,  7,  to  the  posterior  belly  of  the 
digastricus  and  to  the  stylo-hyoideous. 

It  is  chiefly  a  motor  nerve;  and  it  gives  the  ability  to  contract  to  the 
superficial  muscles  of  the  head,  ear,  face,  and  neck.  It  joins  freely  with 
the  sensory  fifth  nerve,  and  furnishes  offsets  also  to  the  integuments;  and 
as  it  supplies  alone  the  posterior  belly  of  the  digastricus  and  the  stylo- 
hyoideus,  it  must  confer  on  them  sensibility  as  well  as  motion. 

The  liyijoglossal  nerve,  14,  is  the  motor  nerve  of  the  tongue.  De- 
scending through  the  neck  with  the  great  bloodvessels  till  it  comes  below 
the  digastric  muscle,  it  is  then  directed  forwards  over  the  carotids  to  the 
submaxillary  region:  it  will  be  continued  in  Plate  xxii. 

As  it  crosses  the  vessels  it  supplies  two  offsets : — one,  descendens  noni, 
3,  enters  the  depressor  muscle  of  the  hyoid  bone,  after  joining  with  the 
spinal  nerves  (Plate  xxiv.);  the  other,  much  smaller,  ends  in  the  thpo- 
hyoideus,  F. 

Branches  of  the  vagus.  Two  branches  of  this  nerve,  viz.,  the  upper 
laryngeal,  1,  and  the  external  laryngeal,  2  (an  offset  of  the  first),  are 
furnished  to  the  larynx;  their  distribution  will  be  referred  to  more  fully 
in  the  description  of  the  Plate  of  the  larynx. 

Branches  of  the  fifth  nerve.  The  auriculo-temporal,  11,  is  a  sensory 
nerve,  and  ascends  with  the  temporal  artery  to  the  side  and  top  of  the 
head;  it  supplies  the  ear  with  the  attrahent  muscle,  and  the  parotid  gland. 
The  mylO'hyoid  branch,  12,  lies  below  the  jaw,  and  ends  in  the  anterior 
belly  of  the  digastricus,  and  the  mylo-hyoideus :  contractility  and  sensi- 
bility are  given  to  those  muscles  by  the  nerve. 

The  great  .auricular  nerve,  10,  of  the  cervical  plexus  is  displayed  in 
Plate  xvi.  In  this  Figure  the  communicating  branches,  9,  through  the 
parotid  to  the  facial  nerre  are  brought  into  view. 


PLATE  XVI 


MUSCLKS    OF    THE   SUBCLAVIAN    REGION. 


153 


DESCRIPTION  OF  PLATE  XVIII. 


The  dissection  of  the  subclaviiiii  bloodvessels  with  the  contiguous 
nerves  and  muscles  is  portrayed  in  this  Plate. 

This  view  has  been  obtained  by  cutting  through  the  sterno-mastoi- 
deus  muscle,  after  the  dissection  of  the  posterior  triangular  space;  and  by 
sawing  through  the  clavicle  and  removing  the  inner  end.  On  the  sec- 
tion of  the  clavicle  the  shoulder  falls  back,  and  the  subclavius  and 
omo-hyoideus  muscles  are  stretched. 

MUSCLES  OF  THE  SUBCLAVIAN  REGION. 

Only  the  subclavius,  the  posterior  belly  of  the  omo-hyoideus,  and  the 
anterior  scalenus  will  be  now  referred  to,  the  other  muscles  having  been 
described  in  other  dissections. 


A.  Pectoralis  major,  cut. 

B.  Intercostal  muscles  of  the  first 

space. 

C.  Subclavius  miiscle. 

D.  Omo-hyoideus — posterior  belly. 

E.  Omo-hyoideus — anterior  belly. 
G.  Sterno-hyoideus. 


H.  Sterno-thyroideus. 

J.  Sternal  part  of  the  sterno-mastoi- 

deus. 
K.  Clavicular  part  of  sterno-mastoi- 

deus,  cut. 
L.  Anterior  scalenus. 
N.  Middle  scalenus. 


Anterior  scalenus,  L.  The  connections  of  the  muscle  may  be  here 
studied:  the  attachments  are  given  at  p.  123.  It  lies  beneath  the  sterno- 
mastoid  and  omo-hyoid  muscles;  and  it  is  connected  with  the  following 
vessels  and  nerves.  In  front  of  it  lies  the  subclavian  vein,  p,  with  the 
external  jugular,  s,  and  anterior  jugular,  v;  and  along  the  inner  edge  de- 
scends the  large  internal  jugular  vein,  r.  Beneath  it  is  the  subclavian 
artery,  l,  and  on  it  are  three  small  arteries,  supra-scapular,  I,  transverse 
cervical,  h,  and  ascending  cervical,  /.  Issuing  from  beneath  the  muscle 
are  the  large  cervical  nerves;  and  running  down  in  front  of  it  is  the 
phrenic  nerve,  3. 


154 


ILLUSTRATIONS    OF    DISSECTIONS. 


Omo-hyoideus,  B.  The  posterior  belly  of  this  muscle  is  attached 
behind  to  the  upper  border  of  the  scapula,  and  ends  in  front  in  a  tendon 
beneath  the  sterno-mastoideus.  It  receives  a  small  vessel  from  the 
supra-scapular,  and  a  nerve  from  the  descendens  noni;  and  the  supra- 
scapular vessels,  /  and  tv,  and  the  supra-scapular  nerve,  9,  course  back- 
wards with  it.     See  also  Plate  xv.,  and  p.  123. 

Suhclaviiis  muscle,  C.  In  Plate  ii.  this  may  be  viewed  in  its  natural 
state,  surrounded  by  a  sheath  of  fascia.  It  arises  from  the  first  rib  where 
the  bone  and  cartilage  join;  and  it  is  inserted  into  the  grooved  under 
surface  of  the  clavicle.  The  inner  part  of  the  muscle  shows  a  ragged 
edge,  where  was  detached  from  the  bone. 


THE  SUBCLAVIAN  ARTERY  AND  ITS   BRANCHES. 

The  subclavian  artery  runs  through  the  lower  part  of  the  neck,  and 
gives  branches  to  the  chest,  the  shoulder,  the  neck,  and  the  brain. 


a.  First    part    of    the    subclavian 

trunk, 
6.  Third  part  of  the  subclavian. 

c.  Common  carotid  artery. 

d.  Inferior  thyroid  artery. 


/.  Ascending  cervical  artery. 
li.  Transverse  cervical  artery. 
I.  Supra-scapular  artery. 
n.  Internal  mammary  artery. 


The  subclavian  artery  of  the  right  side  begins  opposite  the  inner  end 
of  the  clavicle,  where  the  innominate  trunk  bifurcates,  and  ends  at  the 
lower  border  of  the  first  rib  by  becoming  axillary.  Between  those  points 
the  artery  forms  an  arch  with  the  convexity  upwards,  which  lies  between 
the  scaleni  muscles.  Its  numerous  connections  will  be  best  learnt  by 
dividing  the  trunk  of  the  artery  into  three  parts: — one  inside,  one 
beneath,  and  one  outside  the  anterior  scalenus. 

The  first  part  of  the  artery,  a,  is  concealed  by  the  muscles  of  the 
front  of  the  neck,  viz.,  sterno-mastoideus,  J,  sterno-hyoideus,  G,  and 
sterno-thyroideus,  H;  also  by  the  integuments  and  the  platysma.  It  lies 
deeply,  but  not  in  contact  with  the  spinal  column. 

Lying  nearihe  chest  and  below  the  artery  is  the  arch  of  the  subclavian 
and  innominate  veins;  and  crossing  it  at  right  angles  is  the  internal 
jugular  vein,  r,  with  the  vertebral  vein  beneath  this.  And  in  front  of 
the  artery  though  separated  by  muscles  is  the  anterior  jugular  vein,  v. 

The  vagus  nerve,  10,  crosses  over  the  artery  inside  the  jugular  vein, 


'  THE    SUBCLAVIAN    ARTERY    AND    ITS    BRANCHES.  155 

together  with  some  branches  of  tlie  sympathetic;  and  the  recurrent 
branch  of  the  vagus,  and  the  cord  of  the  sympathetic,  lie  beneath  it 
(Plate  xxiv.). 

The  second  or  middle  par:  of  the  artery,  the  shortest  and  highest,  is 
covered  by  the  anterior  scalenus,  L,  and  the  sterno-mastoideus,  K;  and 
rests  on  the  middle  scalenus,  N. 

No  vein  touches  the  artery  in  the  second  part,  for  the  anterior  scalenus 
intervenes  between  the  subclavian  vein  and  artery.  Two  arteries,  trans- 
verse cervical,  li,  and  supra-scapular,  /,  lie  near  the  line  of  the  subclavian 
trunk,  the  former  being  rather  above,  and  the  latter  below  it. 

The  lower  cervical  nerves  are  above  the  vessel  between  the  scaleni; 
and  the  phrenic,  3,  crosses  it,  but  separated  by  the  scalenus  anticus. 

The  outer  or  tliird  part,  h,  is  the  most  superficial,  and  decends  over 
the  first  rib  to  the  axillary  space,  crossing  beneath  the  omo-hyoideus,  D, 
the  subclavius,  0,  and  the  clavicle.  This  jiart  appears  in  the  posterior 
triangular  space  of  the  neck  (Plate  xv.);  and  its  connections  are  described 
in  p.  126. 

Into  the  concavity  of  the  arch  of  the  bloodvessel  the  bag  of  the  pleura 
projects,  for  this  membrane  rises  above  the  first  rib,  and  comes  in  contact 
with  the  first  and  second  parts  of  the  subclavian  artery:  this  connection 
of  the  serous  membrane  must  be  remembered  when  ligature  of  the  second 
part  of  the  artery  is  to  be  undertaken.  Alterations  affecting  the  arch 
have  been  dwelt  on  in  p.  129. 

Number  and  position  of  tlie  branches.  Usually  four  branches  arise 
from  the  artery  in  the  following  manner; — three  are  connected  with  the 
first  part,  and  one  with  the  second  part;  whilst  no  branch,  as  a  rule, 
comes  from  the  third  part.  Very  commonly,  however  (Quain),  an  offset 
(posterior  scapular)  of  the  branch,  h,  is  attached  to  the  last  part  of  the 
subclavian  trunk. 

From  the  position  of  the  branches,  the  connections,  and  the  difference 
in  the  depth  of  the  ends  of  the  subclavian  trunk,  the  third  or  external 
part,  b,  will  be  best  suited  for  ligature  on  account  of  its  comparative  free- 
dom from  any  branch,  and  its  easily  accessible  position.  As  the  second 
part  gives  origin  commonly  to  but  one  branch  it  may  admit  of  being  tied 
under  some  circumstances.  Whilst  the  inner  or  first  part  is  so  beset  by 
branches  as  not  to  possess  commonly  an  interval  sufficient  for  the  appli- 
cation of  a  ligature  without  secondary  hemorrhage.     On  the  left  side  the 


156  ILLUSTRATIONS    OF    DISSECTIONS. 

complicated  connections  forbid  the  attempt  to.  put  a  thread  on  tlie  first 
part. 

Ligature.  The  steps  of  the  operation  for  securing  the  artery  in  the 
third  part,  or  beyond  the  scalenus,  have  been  detailed  at  j).  129. 

Should  the  less  usual  operation  of  tying  the  second  part  of  the  artery 
be  resorted  to,  the  clavicular  piece  of  the  sterno-mastoideus  and  the  an- 
terior scalenus  would  have  to  be  cut  through.  In  dividing  the  scalenus 
great  care  should  be  taken  of  the  phrenic  nerve,  3,  on  its  front.  Ordi- 
narily the  external  jugular  vein  lies  outside  the  scalenus :  with  the  position 
here  taken  it  would  need  to  be  cut  through,  and  the  ends  would  reouire 
to  be  tied. 

Branches  of  the  subclavian  artery.  At  their  origin  the  branches  are 
concealed  by  the  jugular  vein  and  the  anterior  scalenus,  but  in  Plate  xxiv. 
most  may  be  seen.  From  the  first  part  come  the  vertebral,  the  thyroid 
axis,  a;nd  the  internal  mammary;  and  from  the  second  part,  the  upper 
intercostal,  with  a  small  branch  to  the  spinal  canal  (Quain). 

1.  The  vertebral  is  the  first  branch,  and  ascends  to  the  brain  through 
the  apertures  in  tlie  six  upper  cervical  vertebrae. 

2.  The  thyroid  axis,  a  short  thick  trunk,  splits  into  the  three  follow- 
ing;— Inferior  thyroid,  d.  This  is  a  tortuous  artery,  and  ends  in  the 
thyroid  body:  an  offset,  the  ascending  cervical,  f,  lies  between  the  anterior 
scalenus  and  the  larger  anterior  rectus,  supplying  oJIsets  to  both,  and  to 
the  spinal  canal.  The  transverse  cervical,  h,  crosses  the  scalenus,  and 
ends  under  the  trapezius  by  dividing  into  two.  The  supra- sca^ndar,  I, 
courses  along  the  clavicle  to  the  scapula,  on  the  dorsum  of  which  it  rami- 
fies. 

3.  The  inte7'nctl  mammary ,  n,  arises  opposite  the  vertebral  and  beneath 
the  jugular  vein:  it  enters  the  thorax  through  the  upper  opening,  and  is 
.continued  to  the  wall  of  the  abdomen. 

The  superior  intercostal  (intercosto-cervical)  arises  under  the  scalenus: 
it  supplies  offsets  to  the  upper  two  intercostal  spaces;  and  a  large  branch 
to  the  back  of  the  neck  (deep  cervical),  which  is  delineated  in  Plate  xix. 

SUBCLAVIAN   AND  JUGULAR  VEINS. 

The  veins  of  the  arm  and  of  the  same  side  of  the  neck  meet  at  the  top 
of  the  thorax,  and  blend  in  one  large  trunk — the  innominate:  the  limb 
vein  is  called  subclavian,  and  the  neck  veins  jugular. 


neUves  of  the  subclavian  region.  157 


jj.  Subclavian  vein. 

r.  Internal  jugular  vein. 

s.  External  jugular  vein. 


t.  Transverse  cervical  vein. 
V.  Anterior  jugular  vein. 
to.  Supra-scapular  vein. 


T\\Q subclavian  vein,  p,  is  rather  shorter  than  its  corresponding  artery, 
and  ends  near  the  inner  border  of  the  scalenus  by  joining  the  internal 
jugular  to  form  the  innominate  trunk.  Arched  like  the  artery,  it  is 
placed  in  front  of  the  scalenus,  and  commonly  below  the  level  of  the 
clavicle.  Valves  exist  in  the  trunk  outside  the  place  of  entrance  of  the 
external  jugular,  s. 

The  veins  joining  it  are  the  external  and  anterior  jugular,  and  the 
vertebral.  At  the  back  of  the  vein,  near  the  internal  jugular,  the  right 
lymphatic  duct  opens;  and  at  a  similar  spot  on  the  left  side  the  thoracic 
duct  is  received. 

External  and  anterior  jugular  veins.  The  ending  of  these  veins  is 
seen  in  this  Plate,  and  their  course  is  described  in  p.  131.  The  external 
jugular,  r,  receives  the  transverse  cervical  branch,  t,  and  the  supra-scap- 
ular w,  and  joins  the  subclavian  vein  outside  the  scalenus  anticus.  The 
anterior  jugular,  v,  enters  either  the  subclavian  vein  or  the  external  jug- 
ular: when  this  vein  is  tributary  to  the  external  jugular  it  wants  valves 
(Strutliers). 

Internal  jugular  vein,  r.  The  lower  dilatation  of  the  vein  is  laid  bare. 
Before  its  junction  with  the  subclavian  it  is  narrowed,  and  at  the  less 
wide  part  is  a  pair  of  valves  to  prevent  the  blood  rushing  backwards  to  the 
neck.  * 

The  innominate  is  the  large  venous  trunk  formed  by  the  union  of  the 
subclavian  and  internal  jugular  veins:  it  enters  the  chest,  and  joins  with 
its  fellow  in  the  upper  cava.  The  connections  of  the  vein  in  the  neck 
may  be  studied  in  the  Figure. 


NERVES  OF  THE  SUBCLAVIAN    REGION. 

Most  of  the  nerves  are  continued  to  distant  parts,  only  two  being  dis- 
tributed to  the  neighboring  muscles. 

*  These  valves  were  first  described  by  Dr.  Struthers.     See  an  account  of  them 
in  the  Edinb.  Med.  Journal  for  Nov.,  1856,  p.  241. 


158  ILLDSTKATIONS    OF    DISSECTIONS. 


1.  Great  auricular  nerve. 

2.  Superficial  cervical  nerve 

3.  Phrenic  nerve. 

4.  Descendens  noni  nerve. 

5.  Fifth  cervical  nerve. 

6.  Sixth  cervical  nerve. 


7.  Seventh  cervical  nerve. 

8.  Eighth  cei-vical  nerve. 

9.  Supra-scapular  nerve. 
10.  Vagus  nerve. 

f    Nerve  to  the  subclavius. 


The  diaphragmatic  (phrenic)  nerve,  3,  springs  from  the  fourth  spinal 
nerve  in  the  cervical  plexus,  and  is  sometimes  connected  with  the  fifth 
spinal  as  it  passes  by  that  trunk.  In  the  neck  it  courses  over  the  anterior 
scalenus  muscle,  crossing  from  the  outer  to  the  inner  edge;  and  entering 
the  chest  beneath  the  innominate  vein,  it  is  transmitted  through  that 
cavity  to  the  diaphragm.     It  is  the  motor  nerve  of  the  diaphragm. 

Descendens  noni  nerve,  4.  For  the  beginning  of  this  branch  of  the 
hypoglossal,  see  Plate  xvii.  At  the  lower  part  of  the  neck  it  ends  in 
branches  for  the  sterno-hyoideus,  G,  sterno-thyroideus,  H,  and  the  pos- 
terior belly  of  the  omo-hyoideus,  D,  as  well  as  the  anterior  belly  of  the 
same  muscle. 

Bracldal  plexus.  The  lower  four  cervical  nerves,  5,  6,  7,  8,  join  with 
•the  first  dorsal  to  form  the  plexus.  The  branches  of  the  plexus  above  the 
■clavicle  are  enumerated  in  p.  134;  but  only  two,  nerve  to  the  subclavius, 
■f ,  and  the  supra-scapular,  9,  are  seen  in  a  front-view  of  this  region. 

The  vagus  nerve,  10,  passes  through  the  neck  and  thorax  to  the  belly. 
At  the  lower  part  of  the  neck,  on  the  right  side,  it  occupies  the  interval 
between  the  jugular  vein  and  the  carotid  artery,  and  crosses  over  the  sub- 
clavian artery  but  beneath  the  innominate  vein. 

It  furnishes  a  small  cardiac  branch  near  the  subclavian  artery;  and 
■close  below  that  vessel  it  sends  backwards  the  recurrent  or  inferior  laryn- 
geal nerve. 


PLATL  XIX. 


■^ 


^ 


DEEP.  MUSCLES  OF  THE  NECK.  159 


DESCRIPTIOX  OF  PLATE  XIX. 


A  viETV  of  the  deep  muscles,  and  of  the  vessels  and  nerves  at  the  back 
of  the  neck,  is  here  given. 

After  the  integuments  and  the  superficial  muscles  have  been  reflected 
the  complexus  is  to  be  divided  near  the  head;  and  this  last  muscle  being 
thrown  down  and  out,  the  vessels  and  nerves  are  to  be  sought  in  the  dense 
tissue  and  fascia  in  which  they  are  imbedded.  Lastly,  the  muscles  are 
to  be  defined. 

DEEP  MUSCLES  OF  THE  NECK. 

Extensor  and  rotator  muscles  of  the  head  and  neck  lie  beneath  the 
complexus,  B.  Between  the  head  and  the  first  two  vertebrae,  and  corre- 
sponding with  the  interspinales,  are  placed  the  recti  muscles;  and  laterally 
there  are  two  other  small  muscles,  the  obliqui.  Occupying  the  vertebral 
groove  is  the  semispinalis  colli. 


A.  Sterno-mastoideus, 

B.  Complexus  cut  through. 

C.  Semispinalis  colli. 

D.  Obliquus  inferior. 


F.  Obliquua  superior. 

G.  Rectus  posticus  major. 
H.  Rectus  posticus  minor. 


The  complexus  muscle,  B,  is  attached  by  the  outer  edge  to  the  trans- 
verse processes  of  the  upper  dorsal  vertebrge,  and  to  the  articular  processes 
of  the  cervical  vertebrge,  except  the  first  two;  and  by  the  inner  edge  it  is 
connected  with  the  spines  of  one  or  two  lower  cervical  and  upper  dorsal 
vertebrae.  It  is  inserted  into  the  mid  part  of  the  occipital  bone  between 
the  curved  lines. 

Towards  the  inner  edge  a  piece  of  the  muscle  possesses  a  middle  ten- 
don, and  this  is  often  described  separately  as  the  hiventer  cervicis. 

If  the  muscles  of  both  sides  act  they  will  maintain  the  head  erect,  or 
will  bring  it  back  (raising  the  face)  according  to  the  degree  of  contraction; 
but  supposing  only  one  to  contract,  the  occiput  will  be  inclined  down  and 
out  towards  the  transverse  processes  of  the  same  side. 


160 


ILLXISTEATIONS    OF    DISSECTIONS. 


SemispinaUs  colli,  0.  Filling  tlie  vertebral  grooye  with  the  multi- 
fidus  spinse,  it  is  attached  externally,  like  the  preceding  muscle,  to  the 
transverse  processes  of  the  ujoper  dorsal  vertebrae,  and  to  the  articular 
processes  of  the  cervical  vertebra,  except  the  first  three;  and  internally 
it  is  inserted  into  the  spines  of  the  cervical  vertebras  below  the  first. 

Acting  with  its  fellow  it  extends  the  spine:  by  itself,  it  rotates  the 
sj)ine,  turning  the  face  to  the  opposite  side. 

The  oUiquus  inferior,  D,  slants  between  the  first  two  vertebrae:  it 
arises  from  the  spine  of  the  axis,  and  is  inserted  into  the  transverse  pro- 
cess of  the  atlas. 

Drawing  backwards  the  lateral  part  of  the  altas  it  rolls  this  bone  round 
the  odontoid  process  of  the  axis,  and  rotates  indirectly  the  head,  moving 
the  face  to  its  own  side. 

The  oNiqims  superior,  F,  arises  from  the  transverse  process  of  the 
atlas,  where  the  preceding  is  attached,  and  is  inserted  into  the  occipital 
bone  between  the  curved  lines,  and  near  the  mastoid  process. 

The  muscle  can  draw  back  the  head;  and  may  check  a  too  great  for- 
ward movement,  as  in  nodding. 

The  rectus  posticus  major,  G,  arises  from  the  spine  of  the  second 
vertebra;  and  widening  as  it  ascends  obliquely,  it  is  inserted  into  the  outer 
half  of  the  lower  curved  line  of  the  occipital  bone,  where  it  is  partly  con- 
cealed by  the  obliquus  superior. 

This  muscle  extends  the  head,  and  brings  the  face  to  its  own  side  by 
moving  the  atlas  round  the  odontoid  process  of  the  axis. 

Rectus  posticus  minor,  H,  arises  from  the  arch  of  the  altas,  close  to 
the  middle  line;  and  is  inserted  into  the  inner  half  of  the  lower  curved 
line  of  the  occipital  bone.     The  muscle  extends  the  head. 

ARTERIES  OF  THE  BACK  OF  THE  NECK. 


Three  arteries  supply  the  back  of  the  neck,  and  connect  the  vessels  of 
the  head  with  those  of  the  trunk.  In  the  neighborhood  of  the  thorax 
small  offsets  of  the  dorsal  arteries  appear. 


a.  Occipital  artery. 
h.  Deep  cervical  branch  of  the  occi- 
pital. 

c.  Offset  to  the  small  rectus  muscle. 

d.  Vertebral  artery. 


e.  Cervical  branch  of  the  vertebral. 
/.  Anastomosis  of  the  vertebral  and 

deep  cervical  arteries. 
g.  Deep  cervical  artery. 
h.  Dorsal  arteries — the  inner  branches. 


NERVEg  OF  THE  BACK  OF  THE  NECK.  161 

The  occipital  artery,  a,  courses  to  the  integuments  of  the  back  of  the 
head  over  the  obliquus  superior  and  the  complexus,  and  beneath  the 
sterno-mastoideus,  the  splenius,  and  the  trachelo-mastoideus:  near  the 
middle  line  it  pierces  the  trapezius. 

It  furnishes  a  cervical  branch,  h,  to  the  neck  (ram.  princeps  cervicis), 
whicli  descends  beneath  the  complexus,  B,  suppl;png  the  deep  muscles, 
and  anastomoses  with  branches  of  the  vertebral  and  deep  cervical  arteries. 
An  offset  passes  over  the  complexus,  and  supplies  the  superficial  muscles. 

The  vertebral  artery,  d,  in  its  course  to  the  interior  of  the  skull  is 
directed  backwards  in  a  groove  on  the  neural  arch  of  the  atlas.  Lying 
deeply  in  the  bottom  of  the  hollow  between  the  large  rectus  and  the  ob- 
lique muscles,  it  furnishes  one  or  two  muscular  offsets,  e,  and  communi- 
cates with  the  contiguous  arteries. 

The  deei)  cervical  artery,  g,  is  the  dorsal  offset  of  the  upper  intercostal 
(p.  156),  and  reaches  the  back  of  the  neck  by  jsassing  between  the  trans- 
Terse  processes  of  the  last  cervical  and  first  dorsal  vertebrae.  At  the 
back  of  the  neck  it  ascends  under  the  complexus  as  high  as  the  axis, 
where  it  communicates  with  the  two  arteries  before  described.  It  sup- 
plies chiefly  the  complexus  and  the  semispinalis  colli. 

The  height  at  which  the  artery  appears  is  very  uncertain ;  and  it  may 
be  rej^resented  by  two  branches  of  different  arteries.  In  obstruction  of 
the  circulation  in  the  common  carotid  the  blood  will  be  conveyed  to  the 
exterior  of  the  head  by  means  of  the  anastomosis  between  the  profunda 
and  the  occipital  artery. 

The  companion  veins  of  the  arteries  have  not  been  included  in  the 
Plate :  they  resemble  the  arteries,  with  the  exception  of  the  vertebral  which 
begins  on  the  back  of  the  head  and  neck,  and  does  not  enter  the  skull. 


NERVES  OF  THE  BACK  OF  THE  NECK. 

The  anatomy  of  the  posterior  primary  branches  of  the  cervical  nerves 
beneath  the  complexus  is  here  shown.  A  part  of  the  small  occipital 
nerve  appears  behind  the  ear. 


1.  First  or  suboccipital  nerve. 

2.  Second  cervical  nerve. 

3.  Third  cervical  nei-ve. 

4.  Fourth  cervical  nerve. 

11 


5.  Fifth  cervical  nerve. 

6.  Sixth  cervical  nerve. 

7.  Seventh  cervical  nerve. 

8.  Small  occipital  nerve. 


162  ILLUSTEATIO^rS    OF    DISSECTIONS. 

Thejirst  nerve,  1,  ap^^ears  beneath  tlie  vertebral  artery,  and  ends  in 
branches  to  the  complexus,  and  the  recti  and  obliqui  muscles:  it  is  joined 
to  the  second  nerve  by  a  loop. 

Other  cervical  nerves.  The  remaining  seven  cervical  nerves  divide 
into  two — inner  and  outer  branches,  as  soon  as  they  leave  the  spinal 
canal. 

The  external  branches  are  not  laid  bare  except  that  of  the  second:  they 
are  small,  and  are  distributed  to  the  muscles  outside  the  complexus,  viz., 
splenius,  cervicalisascendens,  and  transversalis  colli  and  trachelo-mastoi- 
deus. 

The  internal  branches  are  directed  inwards — the  four  highest  over, 
and  the  remaining  three  through  the  semispinalis  colli;  and  at  the  spines 
of  the  vertebrae  those  that  lie  on  the  semispinalis  become  cutaneous.  They 
supply  the  complexus  and  the  muscles  filling  the  vertebral  groove,  with 
the  interspinales.  The  following  are  the  chief  differences  in  these 
nerves: — 

The  branch  of  the  second  nerve,  2,  the  largest  of  all,  pierces  the  com- 
plexus and  trapezius,  and  becoming  cutaneous  is  distributed  to  the  occi- 
put: it  IS  nomad, great  occipital,  and  is  joinod  by  the  small  occipital  nerve, 
8.  It  supplies  branches  to  the  inferior  oblique  and  complexus  muscles; 
and  it  communicates  by  loops  with  the  first  and  third  nerves. 

The  cutaneous  part  of  the  third  nerve,  larger  than  those  below  it, 
sends  upwards  a  branch  to  the  occiput,  which  joins  the  larger  occipital 
nerve. 

The  connecting  pieces  between  the  inner  branches  of  the  first  three 
nerves  are  sometimes  absent.  M.  Cruveilhier  describes  this  looped 
arrangement  as  the  posterior  cervical  plexus. 

The  small  occipital  nerve,  8,  is  an  offset  of  the  cervical  plexus  (Plate 
XV.);-  i':  ends  in  the  integuments  of  the  occiput,  and  joins  the  great  oc- 
cipital nerve. 


PLATE  XX 


H.  IJciickc ,  LitJi. 


MUSCLES   OF   MASTICATION. 


163 


DESCRIPTION  OF  PLATE  XX. 


In  this  dissection  of  tlie  pterygoid  region  the  muscles  of  mastication, 
and  the  internal  maxillary  artery  with  its  branches  can  be  studied.  Most 
of  the  branches  of  the  inferior  maxillary  nerve  come  also  into  sight. 

This  superficial  dissection  will  be  made  by  detaching  and  throwing 
down  the  zygomatic  arch  Avith  the  masseter  muscle,  by  sawing  off  and 
raising  the  coronoid  process  with  the  temporal  muscle:  and  by  removin<' 
the  piece  of  the  ramus  of  the  jaw  between  the  condyle  and  dental  fora- 
men.    After  each  sawing  of  the  bone  the  fat  is  to  be  carefully  removed. 


MUSCLES   OF  MASTICATION. 


The  muscles  employed  in  mastication  are  attached  chiefly  to  the  angle 
and  processes  at  the  back  of  the  lower  jaw;  but  one,  which  occujjies  the 
cheek,  blends  with  the  lip-muscles. 


A.  Temporal  muscle. 

B.  External  pterygoid  muscle. 

C.  Internal  pterygoid  muscle. 

D.  Buccinator  muscle. 

F,  Masseter  muscle. 

G.  Digastric       muscle       (posterior 

beUy). 


H.  Stylo-hyoideus. 

L.  Stylo-glossus. 

N.  Internal  lateral  ligament. 

O.  Styloid  process. 

P.  Duct  of  the  parotid  gland. 


The  temporal  muscle,  A,  arises  from  the  temporal  fossa  on  the  side 
of  the  skull,  and  from  the  upper  part  of  the  temporal  fascia;  and  the 
fibres  converge  to  a  tendon  which  is  attached  to  the  under  surface  of  the 
coronoid  process,  and  to  the  groove  along  the  fore  part  of  the  ramus  of 
the  jaw. 

Comparatively  superficial  above,  the  muscle  passes  below  beneath  the 
zygomatic  arch  and  the  masseter  muscle,  and  rests  on  the  external  ptery- 
goid, B.  Near  the  zygoma  a  stratum  of  fat  intervenes  between  the  fleshy 
fibres  and  the  temporal  fascia. 


164:  ILLUSTRATIONS    OF    DISSECTIONS. 

In  mastication  this  muscle  crushes  the  food  by  raising  the  lower  jaw; 
and  if  the  jaw  has  been  moved  forwards,  the  hinder  fibres  may  be  able  to 
bring  that  bone  backwards,  with  the  aid  of  the  muscles  attached  to  the 
chin. 

The  masseter  muscle,  F,  is  placed  external  to  the  ramus  of  the  jaw. 
It  takes  origin  from  the  lower  border  and  inner  surface  of  the  zygomatic 
arch;  and  it  is  inserted  into  the  outer  surface  of  the  ramus  of  the  jaw, 
from  the  tip  of  the  coronoid  process  to  the  angle,  and  as  far  forwards 
as  the  second  molar  tooth.  The  superficial  fibres  take  a  direction  down 
and  back  across  the  deeper  and  straighter  fibres. 

This  muscle  is  the  external  elevator  of  the  angle  of  the  jaw. 

The  internal  2)tery go  id  muscle,  C,  has  a  position  inside  the  ramus  of 
the  jaw  similar  to  that  of  the  masseter  outside.  The  muscle  arises 
chiefly  from  the  pterygoid  fossa,  but  below  from  the  palate  and  upper 
jaw  bones  by  a  process  which  extends  in  front  of  the  lower  part  of  the 
external  pterygoid  muscle.  It  is  inserted  into  the  inner  surface  of  the 
angle  and  ramus  of  the  jaw  as  high  as  the  dental  foramen. 

It  raises  the  angle  of  the  jaw  m  conjunction  with  the  masseter,  and 
may  be  considered  the  internal  elevator  of  the  angle. 

The  external  pterygoid  muscle,  B,  is  directed  almost  horizontally  back 
and  out  from  the  base  of  the  skull  to  the  condyle  of  the  jaw.  Arising 
from  the  outer  surface  of  the  external  pterygoid  plate,  and  from  the  con- 
tiguous part  of  the  great  wing  of  the  sphenoid  bone  as  high  as  the  crest, 
the  muscle  is  inserted  into  the  front  of  the  neck  of  the  lower  jaw,  and 
into  the  interarticular  fibro-cartilage. 

An  interval  separates  the  attachments  to  the  external  pterygoid  plate 
and  the  great  wing,  through  which  the  internal  maxillary  artery,  d,  usu- 
ally passes. 

If  the  muscles  of  both  sides  act  the  jaw  is  moved  downwards  and  for- 
wards, and  the  front  lower  teeth  pass  beyond  the  upper.  If  only  one 
muscle  acts,  say  the  right,  it  draws  the  condyle  of  the  same  side  further 
into  the  articular  socket,  and  causes  the  chin  to  project  to  the  left  of 
the  middle  line  of  the  head,  the  grinding  teeth  of  the  lower  jaw  passing 
laterally  over  those  of  the  upper  jaw. 

The  luccinator  muscle,  D,  forms  a  thin  fleshy  layer  in  the  cheek 
between  the  mucous  membrane  and  the  teguments.  It  is  attached  to  the 
jaws  opposite  the  molar  teeth,  and  between  the  jaws  at  the  back  of  the 
mouth  to  a  fibrous  band— the  pterygo-maxillary  ligament.     Towards  the 


INTERNAL   MAXILLARY    ARTERY.  165 

corner  of  the  mouth  the  fibres  are  aggregated  together,  and  entering  the 
lips  blend  with  the  orbicularis  oris  muscle. 

In  the  movements  of  the  lips  the  muscle  retracts  the  corner  of  the 
mouth,  and  so  widens  that  aperture,  and  Avrinkles  the  cheek. 

In  mastication  it  is  applied  to  the  jaws,  and  prevents  the  food  escap- 
ing outside  the  teeth;  when  it  is  paralyzed  the  food  distends  it  and  the 
cheek  in  an  inconvenient  manner. 

In  playing  a  wind  instrument  this  muscle  is  flattened,  and  the  fibres 
are  contracted  for  the  purpose  of  driving  the  outgoing  air  througli  the 
channel  of  the  mouth;  but  in  the  use  of  a  blow-pipe  the  muscle  is  dis- 
tended because  the  mouth  is  used  as  a  reservoir,  but  the  fibres  contract 
at  the  same  time,  to  maintain  a  contniuous  and  active  current  of  air. 


INTERNAL  MAXILLARY  ARTERY. 

The  chief  vessel  in  this  dissection  is  the  internal  maxillary  artery, 
which  is  continued  through  the  pterygoid  region  to  the  deep  parts  of 
the  head,  the  nose,  and  the  palate,  supplying  many  offsets. 


a.  External  carotid  artery. 
6.  Posterior  auricular  branch. 

c.  Superficial  temporal  artery. 

d.  Internal  maxillary  artery. 

e.  Inferior  dental  branch. 

/.  Branch  with  the  gustatory  nerve. 


g.  Deep  temporal  artery. 

li.  Buccal  artery. 

I.  Posterior  dental  branch. 

n.  Facial  artery. 

r.  Inferior  labial  branch. 

s.  Masseteric  branch,  cut. 


The  internal  maxillary  artery,  d,  is  one  of  the  terminal  branches 
of  the  external  carotid,  and  runs  upwards  and  inwards  over  or  under  the 
external  pterygoid  muscle  to  the  spheno-maxillary  fossa,  where  it  ends  in 
branches  for  the  nose,  the  palate,  and  the  pharynx.  It  gives  numerous 
branches,  and  these  are  classed  into  three  sets  : — one  external  to  the 
pterygoid  muscle,  another  whilst  the  artery  lies  on  the  muscle,  and  a 
third  internal  to  the  muscle,  or  in  the  si^heno-maxillary  fossa.  The  first 
two  sets  will  be  mainly  referred  to  now. 

The  first  set  of  branches,  two  in  number  (dental  and  meningeal), 
belong  to  the  lower  jaw  and  the  skull. 

The  inferior  dental  artery,  e,  enters  the  canal  in  the  lower  jaw  with 
the  nerve  of  the  same  name,  and  supplies  the  teeth  and  the  lower  j)art  of 


166  ILLUSTRATIONS    OF   DISSECTIONS. 

the  face.  Before  it  enters  the  bone,  a  small  offset  (mylo-hyoid)  descends 
with  a  fine  nerve  in  a  groove  inside  the  ramus  of  the  jaw. 

The  large  or  middle  meningeal  artery  arises  opposite  the  j)receding, 
and  is  concealed  by  the  external  pterygoid:  it  is  delineated  in  Plate 
xxi.,  h. 

A  third  small  artery,  /,  which  has  not  been  described  by  Anatomists, 
runs  with  the  gustatory  nerve,  and  supplies  the  cheek,  and  the  floor  of 
the  mouth  external  to  the  tongue. 

Tlie  second  set  of  hranclies  is  distributed  to  the  muscles  of  mastication 
as  below: — 

The  deep  temporal,  g,  two  in  number,  enter  the  fore  and  hinder  parts 
of  their  muscle.  The  masseteric  branch,  s,  springs  in  common  with  the 
posterior  temporal,  and  enters  the  hinder  border  of  the  masseter:  it  has 
been  cut  in  the  removal  of  the  muscle.  The  buccal  branch,  li,  descends 
to  the  cheek  and  the  buccinator  muscle:  it  anastomoses  with  the  facial 
artery.    Branches  to  the  pterygoid  muscle  are  shown  in  Plate" xxi. 

Third  set  of  tranches.  Only  one  of  these  branches,  the  j^osterior 
dental,  h,  is  seen  in  the  dissection.  It  takes  a  tortuous  course  to  the 
front  of  the  upper  jaw,  where  it  communicates  with  the  infra-orbital:  it 
will  be  given  more  fully  in  Plate  xxiii. 

The  facial  artery,  n,  also  a  branch  of  the  external  carotid  (Plate 
xvii.),  is  displayed  as  it  crosses  the  jaw.  It  ascends  with  a  wavy  course 
to  the  root  of  the  nose,  passing  near  the  corner  of  the  mouth. 

Named  branches  supply  the  lips  and  the  nose,  and  one  of  these  to  the 
lower  part  of  the  face  is  the  inferior  laiial,  r.  Unnamed  branches  ram- 
ify in  the  cheek,  and  anastomose  with  the  buccal  and  transverse  facial 
arteries. 

MAXILLARY  AND  FACIAL  VEINS. 


t.  External  jugular  vein. 
V.  Superficial  temporal. 
w.  Internal  maxillary  vein. 


X.  Facial  vein. 

z.  Deep  facial,  or  anterior  internal 
maxillary. 


The  facial  vein,  x,  begins  near  where  the  companion  artery  ceases, 
and  crosses  the  face  to  the  jaw;  but  it  takes  almost  a  straight  line  from 
the  root  of  the  nose  to  the  front  of  the  masseter  muscle,  and  does  not 
follow  the  windings  of  the  facial  artery.  It  ends  in  the  neck  in  the 
internal  jugular  trunk. 


NERVES  OF  THE  PTERYGOID  REGION.  167 

Besides  branches  received  from  the  orbit  and  the  face,  it  is  joined 
opposite  the  angle  of  the  month  by  a  vein — the  deep  facial,  z,  or  the 
anterior  internal  maxillary,  which  brings  blood  from  the  pterygoid  region 
and  the  upper  jaw. 

Internal  maxillary  vein,  tv.  Only  the  ending  of  this  in  the  external 
jugular  remains, — the  jDlexiform  continuation  of  it  by  the  side  of  the 
artery  having  been  taken  away. 


NERVES  OF  THE  PTERYGOID  REGION. 

The  nerves  appearing  in  this  dissection  are  branches  of  the  inferior 
maxillary  trunk  of  the  fifth  cranial  nerve,  with  the  exception  of  two 
small  nerves,  one  lying  along  the  upper  jaw,  and  another  on  the  lower 
jaw. 


1.  Auriculo-temporal  nerve. 
3.  Inferior  dental  nerve. 

3.  Gustatory  nerve. 

4.  Masseteric  nerve,  cut. 


5.  Buccal  nerve. 

6.  Posterior  dental  nerve. 

8.  Buccal    branches    of     the    facial 
nerve. 


The  anatomy  of  the  inferior  maxillary  nerve  is  described  with  Plate 
xxi. ;  but  the  position  of  its  several  branches  passing  the  external  ptery- 
goid can  be  here  seen  before  the  muscle  is  raised. 

This  large  trunk  of  the  fifth  nerve  is  concealed  as  it  leaves  the  skull 
by  the  external  pterygoid;  and  its  branches  escape  through  the  muscle 
or  at  its  edges.  Appearing  at  the  upper  border  are  the  masseteric  nerve, 
4,  and  the  deejj  temporal  (Plate  xxi.,  8);  and  issuing  at  the  lower  border 
are  three  large  trunks,  viz.,  the  auriculo-temporal,  1,  the  dental,  2,  and 
the  gustatory,  3.  The  buccal  nerve,  5,  comes  forwards  between  the  two 
pieces  of  the  pterygoideus  externus. 

The  posterior  dental  nerve,  6,  a  branch  of  the  upper  maxillary  trunk, 
descends  along  the  upper  jaw  with  its  artery:  its  origin  and  distribution 
may  be  referred  to  in  Plate  xxiii. 


168 


ILJ^USTRATIONS    OF    DISSECTIONS. 


DESCRIPTION  OF  PLATE  XXI. 


This  Illustration  of  the  deep  dissection  of  the  iDterygoid  region  ex- 
hibits the  third  trunk  of  the  fifth  cranial  nerve,  and  the  deep  branches  of 
the  internal  maxillary  artery. 

In  preparing  the  dissection  the  internal  maxillary  artery  should  be 
cut  through,  and  the  condyle  of  the  jaw  having  been  disarticulated  should 
be  drawn  forwards  with  the  external  pterygoid  muscle.  After  the  re- 
moval of  the  fat  the  nerves  and  vessels  will  be  ready  for  learning. 


MUSCLES   OF  MASTICATION. 


The  muscles  described  with  Plate  xx.  are  met  with  again  in  this  view, 
and  they  are  marked  with  the  same  letters  of  reference.  A  better  idea 
of  the  wide  origin  of  the  external  pterygoid  is  obtained  in  tliis  Plate. 


A.  Temporal  muscle. 

B.  External  pterygoid  muscle. 

C.  Internal  pterygoid  muEicle. 

D.  Buccinator  muscle. 

F.  Masseter  muscle. 

G.  Digastric  muscle. 


H.  Zygoma  thrown  down. 
L.  Condyle  of  the  jaw. 
N.  Internal  lateral  ligament. 
O.  Styloid  process,  and  stylo-maxil- 
lary ligament. 


INTERNAL  MAXILLARY  ARTERY. 

The  meningeal  and  the  muscular  branches  of  the  internal  maxillary 
artery,  which  were  hidden  in  Plate  xx.,  are  now  brought  under  notice; 
and  the  other  arteries,  which  are  the  same  as  in  the  preceding  Figure, 
are  marked  by  the  same  letters. 


a.  External  carotid  trunk. 
6.  Large  meningeal  artery. 

c.  Small  meningeal  branch. 

d.  Internal  maxillary  artery. 

e.  Inferior  dental  branch. 

/.  Branch  with  the  gustatory  nerve. 


g.  Deep  temporal  branches. 

li.  Buccal  branch. 

I.  Posterior  dental  branch. 

n.  Facial  artery. 

t.  External  jugular  vein. 


PLATE  XXI 


^r'^'-^m^s. 


INFERIOR    MAXILLARY    NERVE. 


169 


The  large  or  middle  meningeal  artery,  b,  ascends  to  the  head  beneath 
the  external  pterygoid  muscle,  and  enters  the  skull  through  the  foramen 
spinosum  (p.  110).  It  supplies  branches  to  the  temporal  and  external 
pterygoid  muscles,  an  offset  to  the  tympanum  through  the  Glaserian 
fissure,  and  the  following: — 

Small  meningeal  branch,  c.  Arising  from  the  large  meningeal,  it 
enters  the  skull  through  the  foramen  ovale:  an  offset  is  furnished  outside 
the  skull  to  the  internal  pterygoid  with  the  branch  of  nerve  to  that  mus- 
cle. 

INFERIOR  MAXILLARY  NERVE. 

The  branches  of  the  inferior  maxillary  nerve,  whose  lettering  corre- 
sponds with  that  in  Plate  xx.,  are  here  traced  backwards  to  the  foramen 
of  exit  of  their  trunk  from  the  skull. 


1.  Auriculo-temporal  nerve. 

2.  Inferior  dental  nerve. 

3.  Gustatory  nerve. 

4.  Masseteric  branch,  cut. 

5.  Buccal  branch. 


6.  Chorda  tympani  nerve. 

7.  Mylo-hyoid  branch. 

8.  Deep  temporal  branch. 

9.  Branch  to  the  external  pterygoid. 
f    Branch  to  the  internal  pterygoid. 


The  inferior  7naxillary  or  the  third  trunk  of  the  fifth  cranial  nerve 
(Plate  xiii.)  leaves  the  skull  by  the  foramen  ovale,  and  splits  at  once  into 
two  under  the  external  pterygoid  muscle,  viz. — an  anterior  small  part, 
and  a  posterior  large  part.  And  as  the  nerve  is  composed  of  a  motor 
and  a  sensory  root  (p.  108),  the  function  bestowed  by  its  offsets  will  be 
determined  by  their  receiving  filaments  from  only  one  or  from  both 
roots. 

The  smaU  piece  of  the  nerve  breaks  up  into  branches  to  most  of  the 
muscles  of  mastication  as  below: — 

The  masseteric  branch,  3,  courses  above  the  pterygoideus  externus  and 
through  the  sigmoid  notch  to  the  under  surface  of  its  muscle,  in  whose 
fibres  it  can  be  followed  nearly  to  the  anterior  edge:  it  gives  an  offset  to 
the  back  of  the  temporal  muscle. 

The  deep  temporal  branch,  8,  is  directed  upwards  on  the  skull  into 
the  fibres  of  the  temporal  muscle,  and  usually  with  an  artery  of  the  same 
name. 

The  buccal  branch,  5,  pierces  the  external  pterygoid,  and  is  continued 


170  ILLUSTRATIONS    OF   DISSECTIONS. 

over  the  buccinator  towards  the  corner  of  the  mouth;  it  supplies  chiefly 
the  buccinator  muscle  as  well  as  the  integuments  covering,  and  the  mu- 
cous membrane  lining  the  same.  In  the  cheek  it  joins  in  a  plexus, 
buccal,  with  the  facial  nerve  (Plate  xx.,  8).  Two  masticatory  muscles, 
viz.,  the  external  pterygoid  and  the  temporal,  receive  offsets  from  this 
branch. 

A  hranch'  to  the  pterygoideus  externus,  9,  enters  the  under  surface  of 
that  muscle. 

This  smaller  part  of  the  inferior  maxillary  nerve  contains  portions  of 
both  roots;  these  are  disposed  in  a  peculiar  way,  and  give  different  func- 
tions to  the  branches.  Thus  the  nerves  furnished  by  it  to  the  jaw  mus- 
cles— masseter,  temporal,  and  external  pterygoid — are  constructed  from 
both  roots,  like  spinal  nerves,  and  give  sensibility  and  contractility  to 
those  muscles.  The  nerve  to  the  buccinator  on  the  contrary  is  formed 
altogether  by  the  sensory  root,  and  bestows  only  sensibility  on  the  muscle 
and  the  other  parts  to  which  it  is  distributed. 

The  larger  piece  of  the  inferior  maxillary  nerve,  ends  in  three  good- 
sized  trunks,  and  gives  a  branch  to  the  internal  pterygoid  muscle. 

The  auriculo-temporal  nerve,  1,  beginning  generally  by  two  roots,  is 
inclined  backwards  beneath  the  external  pterygoid  muscle,  and  ascends 
finally  with  the  temporal  artery  to  the  integuments  of  the  side  of  the 
head.  It  communicates  largely  with  the  facial  nerve;  and  it  supplies 
also  the  articulation  of  the  jaw,  the  meatus  of  the  ear,  and  the  parotid 
gland. 

The  inferior  dental  nerve,  2,  descends  over  the  pterygoideus  internus 
and  the  internal  lateral  ligament  to  the  dental  foramen  of  the  lower  jaw, 
and  is  distributed  to  the  teeth,  and  the  lower  part  of  the  face. 

A  small  muscular  branch,  mylo-hyoid,  arises  from  the  nerve  near  the 
jaw,  and  runs  in  a  groove  in  the  bone  to  the  anterior  belly  of  the  digafc- 
tricus,  and  the  mylo-hyoideus  (Plate  xvii.). 

The  gustatory  nerve,  3,  is  directed  downwards  to  the  front  of  the  in- 
ternal pterygoid  muscle,  near  the  attachment  to  the  jaw:  its  further 
course  in  the  tongue  will  be  represented  in  Plate  xxii.  Under  the  exter- 
nal pterygoid  muscle  it  is  joined  by  the  chorda  tympani  nerve,  6. 

The  hranch  to  the  internal  pterygoid  muscle,  f,  comes  from  the  large 
part  of  the  inferior  maxillary  trunk,  and  enters  the  under  surface  of  its 
muscle.  Around  the  root  of  this  branch,  and  on  the  inner  or  deep  sur- 
face of  the  large  trunk,  lies  the  otic  ganglion,  which  furnishes  offsets  to 


•INFERIOR    MAXILLARY   NERVE.  171 

two  other  muscles,  viz.,  the  tensor  tympani  and  the  circumflexus  palati: 
this  body  can  be  recognized  only  in  a  view  from  the  inner  side. 

The  large  part  of  the  inferior  maxillary  trunk  receives  fibrils  from 
both  roots  of  the  fifth  nerve,  like  the  smaller  piece;  but  as  the  part  con- 
tributed by  the  sensory  root  is  much  the  largest,  most  of  the  branches 
are  formed  by  this  alone,  and  are  therefore  sensory  in  function.  The 
three  large  trunks,  auriculo-temporal,  1,  dental,  2,  and  gustatory,  3,  are 
solely  sensory  nerves;  and  the  last  is  one  of  the  nerves  of  taste.  The 
muscular  branches  receiving  offsets  from  both  roots,  bestow  sensibility 
and  contractility  on  the  muscles  before  mentioned,  viz.,  the  pterygoideus 
internus,  the  mylo-hyoideus,  the  anterior  belly  of  the  digastricus,  the 
circumflexus  palati,  and  the  tensor  tympani. 

The  cJiorda  tympani  nerve,  6,  is  a  branch  of  a  motor  nerve — the  facial 
(p.  108),  and  issues  from  the  cranium  through,  or  by  the  side  of  the 
Glaserian  fissure.  It  is  applied  to  the  gustatory  under  the  external 
pterygoid  muscle,  and  is  conveyed  by  that  nerve  trunk  to  the  tongue, 
where  it  is  distributed:  at  the  point  of  contact  one  or  two  offsets  join  the 
gustatory. 

The  two  following  pieces  of  fascia,  which  are  called  ligaments,  look 
like  distinct  bands  in  consequence  of  the  removal  of  the  rest  of  the  cer- 
vical fascia,  with  which  they  are  continuous. 

The  internal  lateral  ligament  of  the  articulation  of  the  jaw  N,  is 
attached  by  one  end  to  the  base  of  the  skull,  and  by  the  other  to  the 
margin  of  the  dental  foramen,  and  to  the  bone  above  the  insertion  of  the 
internal  pterygoid  muscle:  it  is  part  of  the  deep  cervical  fascia  projecting 
under  the  jaw. 

The  stylo-maxillary  ligament,  0,  reaches  from  the  styloid  process  to 
the  hinder  and  lower  parts  of  the  ramus  of  the  jaw:  this  piece  of  the  cer- 
vical fascia  is  continuous  below  with  that  separating  the  parotid  and  sub- 
maxillary glands  (Plate  xvi.,  N). 


172  ILLUSTKATIONS    OF    DISSECTIOKS. 


DESCRIPTION  OF  PLATE  XXII. 


The  dissection  of  the  submaxillary  region  is  indicated  in  this  Figure. 

The  steps  of  the  dissection  are  the  following: — The  soft  parts  over  the 
jaw  are  to  be  divided,  and  the  bone  is  to  be  sawn  through  rather  on  the 
right  of  the  symphysis;  then,  the  tongue  having  been  drawn  out  of  the 
mouth,  the  mucous  membrane  is  to  be  cut  along  it  below,  to  trace  for- 
wards the  vessels  and  nerves. 

To  make  tense  the  muscles,  fasten  down  the  os  hyoides  with  a  stitch 
to  one  of  the  firm  surrounding  parts. 


MUSCLES  OF  THE  TONGUE  AND  THE  HYOID  BONE. 

Extrinsic  muscles  of  the  tongue  and  elevators  of  the  os  hyoides  oc- 
cupy the  interval  between  the  tongue  and  that  bone. 


A.  Mylo-hyoideus,  reflected. 

B.  Genio-hyoideus. 

C.  Genio-glossus. 

D.  Hyo-glossus. 

E.  Stylo-glossus, 

F.  Stylo-hyoideus. 

G.  Middle  constrictor. 
H.  Digastricus. 


J.  Inferior  constrictor. 

K.  Thyro-hyoideus. 

L.  Omo-hyoideus. 

N.  Sterno  hyoideus. 

O.  Stylo-hyoid  ligament. 

P.  Great  cornu  of  the  hyoid  bone. 

Q,  Thyroid  cartilage. 


Elevators  of  the  os  hyoides.  Some  of  the  muscles  of  this  group,  viz., 
the  mylo-hyoideus,  A,  the  stylo-hyoideus,  F,  and  the  digastricus,  H,  have 
been  described  (p.  144) :  the  remaining  elevator  is  given  below. 

Genio-hyoideus,  B.  It  arises  from  an  eminence  inside  the  symphysis 
of  the  jaw,  and  is  inserted  below  into  the  centre  of  the  body  of  the  hyoid 
bone.  The  muscle  touches  its  fellow  along  the  middle  line,  and  lies  be- 
tween the  genio-glossus,  C,  and  the  mylo-hyoideus,  A. 

When  the  mouth  is  shut  the  muscle  will  raise  the  hyoid  bone;  or  the 


-j^i-x-p:<i5v.-. 


PLATE  XXI 


MUSCLES    OF   THE   TONGUE    AND   THE    HYOID    BONE.  173 

OS  hyoides  being  fixed,  ifc  will  help  to  bring  down  the  jaw,  as  in  the  act 
of  opening  the  mouth. 

Extrinsic  iongne  muscles.  There  are  four  on  each  side,  viz.,  hyo- 
glossus,  genio-glossus,  stylo-glossus,  and  chondro-glossus :  only  the  three 
first  are  now  laid  bare. 

Hyo-glossus,  D.  This  thin  muscle  arises  from  the  hyoid  bone,  viz., 
from  the  great  cornu  by  one  part  (cerato-glossus),  and  from  the  body  of 
the  hyoid  bone  by  another  *  (basio-glossus).  From  this  attachment  the 
fibres  ascend  and  enter  the  side  of  the  tongue. 

With  the  OS  hyoides  fixed  the  hyo-glossus  can  depress  the  tongue  in 
the  floor  of  the  month,  and  give  to  that  organ  a  rounded  form.  Sup- 
l^osing  the  tongue  the  fixed  point  the  muscle  will  raise  the  hyoid  bone, 
preparatory  to  swallowing. 

The  stylo-glossus,  E,  arises  from  the  styloid  process  and  the  stylo- 
maxillary  ligament  (Plate  xx.),  and  enters  the  back  of  the  tongue;  but 
its  fibres  extend  forwards  underneath  the  side  of  the  tongue  to  the  tip 
where  they  blend  with  their  fellows. 

The  muscles  of  ojDposite  sides  contracting  will  draw  back  and  up  the 
base  of  the  tongue;  and  by  the  action  of  one  muscle  the  point  of  the 
tongue  Avill  be  turned  to  the  same  side  of  the  mouth. 

Genio-liyo-glossus,  C.  Shaped  like  a  fan,  it  arises  by  a  narrowed  part 
from  a  tubercle  inside  the  symphysis  of  the  jaw;  and  it  is  inserted  along 
the  middle  of  the  tongue  from  tip  to  root,  as  Avell  as  into  the  body  of  the 
hyoid  bone.  In  contact  with  its  fellow  by  the  inner  surface,  the  anterior 
edge  is  covered  by  the  mucous  membrane  of  the  mouth,  and  the  posterior  ' 
touches  the  genio-hyoideus,  B. 

All  the  fibres  contracting  the  tongue  will  be  sunk  in  the  floor  of  the 
mouth,  and  notably  its  middle  part,  so  as  to  give  a  concavity  to  the 
upper  surface.  If  only  the  lower  fibres  act  they  will  raise  the  hyoid 
bone,  and  put  forwards  the  tongue  between  the  teeth:  by  means  of  the 
last  mentioned  fibres  the  muscle  will  be  able  to  dilate  the  pharynx 
anteriorly. 

The  stylo-hyoicl  ligament,  0,  stretches  between  the  end  of  the  styloid 
process  and  the  small  cornu  of  the  hyoid  bone.  Below,  it  lies  beneath 
the  hyo-glossus,   and  gives  attachment  to  the  middle  constrictor,   G. 

*  A  third  fleshy  slip  (chondro-glossusj,  which  is  attached  to  the  small  cornu  of 
the  bone,  is  considered  to  form  part  of  the  muscle. 


174  ILLUSTRATIONS    OF   DISSECTIONS. 

Sometimes  this  band  is  large  and  cartilaginous  or  even  osseous;  at  other 
times  it  is  slight,  and  so  membranous  as  not  to  be  recognized. 

The  Pharynx.  In  front  of  the  "carotid  bloodvessels  is  the  upper  di- 
lated part  of  the  gullet,  or  the  pharynx.  Its  wall  contains  thin  muscles 
which  overlap  one  another,  and  the  chief  of  these  are  called  constrictors: 
two  are  marked  with  G  and  J,  but  they  will  be  more  fully  noticed  in 
Plate  XXV. 

SALIVAEY  GLANDS. 

The  sublingual  gland  and  parts  of  the  submaxillary  and  parotid,  are 
exposed  in  the  dissection. 


R.  Sublingual  gland. 

S.  Piece  of  the  submaxillary. 


T.  Part  of  the  parotid, 
f  Wharton's  duct. 


Submaxillary  gland,  S.  A  deep  part  of  the  gland  projects  beneath  the 
mylo-hyoid  muscle,  and  with  it  the  following  excretory  duct  is  con- 
nected:— 

The  duct  of  the  gland,  f,  (Wharton's,)  is  about  two  inches  long;  it 
ascends  beneath  the  gustatory  nerve  and  the  sublingual  gland  to  the  floor 
of  the  mouth,  and  ends  in  an  eminence  on  the  side  of  the  fraenum 
linguae. 

The  suUingual  gland,  E,  lies  under  the  fore  part  of  the  tongue, 
where  it  forms  a  prominence,  but  it  is  separated  from  the  cavity  of  the 
mouth  by  the  mucous  membrane.  Elongated  from  before  back,  it  is 
about  one  inch  and  a  half  in  length,  and  meets  its  fellow  in  front. 

Its  ducts  are  numerous  (8  to  20),  and  open  for  the  most  part  by  sep- 
arate orifices  in  the  floor  of  the  mouth,  but  some  join  the  duct  of  the 
submaxillary  gland. 

LINGUAL  VESSELS. 

The  vessels  of  the  tongue  are  few  in  number,  in  comparison  with  the 
nerves,  there  being  but  one  on  each  side. 


a.  Common  carotid  trunk. 
h.  External  carotid  artery. 

c.  Upper  thyroid  branch. 

d.  Lingual  artery. 

e.  Ranine  branch. 


/.  Sublingual  branch. 
g.  Facial  artery,  cut. 
Ji.  Occipital  artery. 

i.  Branch  of  tlie  sublingual  artery. 

I.  Internal  jugular  vein. 


NERVES  OF  THE  TONGUE. 


175 


The  Ungual  artery,  d,  springing  from  the  external  carotid,  runs  ob- 
liquely upwards  beneath  the  hyo-glossus  to  the  under  surface  of  the 
tonoue,  where  it  takes  the  name  ranine,  and  continues  along  the  middle 
line  to  the  tip — distributing  offsets.  Near  the  front  of  the  tongue  the 
arteries  of  opposite  sides  correspond  with  the  fraenum  linguai  in  position, 
and  may  be  cut  when  that  fold  of  the  mucous  membrane  is  snipped  with 
a  scissors  in  tongue-tied  infants. 

A  few  named  branches  come  from  the  artery:  the  most  unimportant 
is  the  hyoicl  branch,  which  supplies  one  or  more  of  the  muscles  attached 
to  the  OS  hyoides. 

Beneath  the  hyo-glossus  a  dorsal  lingual  branch  takes  its  origin. 
And  at  the  fore  part  of  that  muscle  arises  the  sublingual  branch,  f,  which 
supplies  the  gland  of  the  same  name  and  the  contiguous  muscles,  and 
joins  the  artery  of  the  opposite  side  by  means  of  the  twig,  i. 

Lingual  vein. — Its  anatomy  is  similar  to  that  of  the  artery,  and  it 
ends  in  the  internal  jugular  vein. 


NERVES  OF  THE  TONGUE. 


Six  large  nerves  end  in  the  tongue,  three  in  each  half  ;  and  the  three 
of  the  right  side  are  delineated  as  they  course  through  the  submaxillary 
region. 


1.  Glosso-pharyngeal  nerve. 

2.  Hypoglossal  nerve. 

3.  Descendens  noni  branch. 

4.  Upper  laryngeal  nerve. 


5.  Gustatory  nerve. 

6.  Submaxillary  ganglion. 

7.  Loop  between  the  gustatory  and 

hypoglossal  nerves. 


The  hgjyoglossal  nerve,  2  (twelfth  cranial,  Plate  xxiv.),  is  the  motor 
nerve  of  the  tongue.  Coursing  with  the  lingual  artery  as  far  as  the  hyo- 
glossus  it  passes  over  this  muscle,  and  enters  the  fibres  of  the  genio-hyo- 
glossus,  in  which  it  is  continued  to  the  tip  of  the  tongue,  gradually  de= 
creasing  in  size  by  the  supply  of.  offsets. 

On  the  hyo-glossus  it  furnishes  branches  to  three  extrinsic  tongue 
muscles — the  hyo,  stylo,  and  genio-glossus;  and  to  one  elevator  of  the 
hyoid  bone— genio-hyoideus.  It  joins  the  gustatory  nerve,  5,  by  means 
of  the  loop,  7. 

The  glosso-pharyngeal  nerve,  1  (ninth  cranial),  taking  the  course  of 


1T6  ILLUSTEATION6   OF   DISSECTIONS. 

the  stylo-pharyngeus  muscle  (Plate  xxiv.),  enters  beneath  the  hyo-glossus 
to  reach  the  mucous  membrane  and  the  papilla  of  the  hinder  third,  and 
the  lateral  part  of  the  tongue.  Beneath  the  hyo-glossus  muscle  it  fur- 
nishes offsets  to  the  pharynx,  the  arches  of  the  soft  palate,  and  the  tonsil. 

The  nerve  confers  sensibility  on  the  mucous  membrane  of  the  pha- 
rynx, and  gives  the  faculty  of  tasting  in  the  back  of  the  tongue  and  in 
the  pillars  of  the  soft  palate. 

Hhe  gustatory  nerve,  5,  coming  from  the  pterygoid  region  (Plate  xxi.) 
appears  between  the  jaw  and  the  internal  pterygoid  muscle,  and  courses 
forwards  along  the  under  surface  of  the  tongue  to  the  tip.  At  first  the 
nerve  rests  against  the  prominence  inside  the  last  molar  tooth;  and  in 
the  rest  of  its  extent  in  the  tongue  it  lies  near  the  edge,  covered  by  the 
mucous  membrane. 

Offsets  from  it  supply  the  mucous  membrane  of  the  floor  of  the  mouth, 
the  submaxillary  and  sublingual  glands,  and  the  tongue  in  front  of  the 
distribution  of  the  glosso-pharyngeal  nerve — especially  the  mucous  mem- 
brane and  the  papillae. 

As  this  branch  of  the  fifth  cranial  nerve  does  not  receive  any  filaments 
of  the  motor  root  (p.  171)  its  function  is  sensory;  and  the  faculty  of 
tasting  in  the  fore  part  of  the  tongue  is  dependent  upon  it. 

Suhmaxillary  ganglion,  7.  This  little  body  resembles  the  lenticular 
ganglion  in  the  orbit  (Plate  xiv.),  and  is  connected  with  the  branch  of 
the  fifth  nerve  distributed  to  the  tongue.  Smaller  than  the  lenticular 
ganglion,  and  occasionally  reddish  in  color,  it  lies  just  above  the  sub- 
maxillary gland. 

Some  branches  are  furnished  to  the  submaxillary  gland  and  the  mu- 
cous membrane  of  the  mouth. 

Other  branches,  sometimes  called  roots,  join  with  the  surrounding 
nerves,  like  the  communicating  branches  of  the  lenticular  ganglion. 
Thus  the  ganglion  is  connected  above  with  the  gustatory — a  sensory 
nerve;  with  the  facial— a  motor  nerve,  by  means  of  the  chorda  tympani 
(p.  171),  which  runs  by  the  side  of  the  gustatory  to  the  tongue,  and  gives 
a  slender  thread  to  the  back  of  the  ganglion;  and  with  the  sympathetic 
through  the  plexus  of  that  nerve  on  the  facial  artery. 


PLATE  XXIII 


f^^ 


ll.rirn.k.-    I,!!l, 


80ME    MUSCLES    OF    THE    FACE, 


177 


DESCRIPTION  OF  PLATE  XXIII. 


In  this  dissection  the  second  trunk  of  the  tiftli  nerve,  and  a  part  of 
the  internal  maxillary  artery,  are  brought  into  view. 

Sujiposing  the  head  and  the  orbit  opened,  the  dissection  will  be  com- 
pleted by  removing  the  outer  wall  of  the  orbit,  and  the  side  of  the  cra- 
nium forming  part  of  the  middle  fossa  of  the  base  of  the  skull. 


SOilE   MUSCLES   OF  THE   FACE. 

Some  of  the  muscles  of  the  eyelids  and  upper  lip  being  partly  dis- 
played will  be  referred  to  shortly;  the  other  muscles,  viz.,  those  of  mas- 
tication, have  received  sufficient  notice  already. 


A.  External  pterygoid  muscle. 

B.  Masseter  muscle. 

C.  Buccinator  muscle. 

D.  Levator  anguli  oris. 

E.  Levator  labii  superioris. 


F.  Levator  lab.  sup.  alasque  nasi. 

G.  Orbicularis  palpebrarum. 
H.  Rectus  oculi  superior. 

I.  Antrum  maxillare. 
L.  Oliquus  oculi  inferior. 


Orbicularis  palpebrarum,  G.  This  thin  sphincter  muscle  occupies 
the  eyelids,  forming  loops  around  their  aperture,  and  extends  beyond  the 
margin  of  the  orbital  cavity. 

When  the  fibres  contract  the  lids  are  closed,  the  upper  one  being 
sj)ecially  brought  down;  and  the  niteguments  around  the  eye  are  wrin- 
kled, and  drawn  towards  the  nose.  In  paralysis  of  the  muscle  the  eye- 
lids cannot  be  brought  together,  and  the  eyeball  remains  constantly 
uncovered. 

Elevators  of  the  upper  lip).  Three  muscles  raise  the  upper  lip,  viz. ,  a 
common  and  a  special  elevator,  and  an  elevator  of  the  angle  of  the  mouth. 

The  elevator  of  the  angle,  D,  arises  from  the  canine  fossa  of  the  upper 
jaw  bone,  and  blends  at  the  corner  of  the  mouth  with  other  muscles. 

The  special  elevator,  E,  arises  from  the  margin  of  the  orbit  over  the 

infra-orbital  foramen,  and  joins  the  sj)hincter  of  the  mouth. 
12 


178 


ILLUSTRATIONS    OF    DISSECTIONS. 


The  common  elevator,  F,  arises  from  tlie  upper  jaw  bone  at  the  inner 
side  of  the  orbit,  and  ends  at  the  mouth  like  the  preceding  :  it  is  attached 
also  to  the  wing  of  the  nose  by  a  separate  slip. 

These  muscles  contracting  together  will  raise  the  upper  lip;  but  the 
elevator  of  the  angle  can  act  independently  of  the  others,  and  raise  the 
corner  of  the  mouth.  Commonly,  elevation  of  the  lip  and  of  the  wing 
of  the  nose  follows  forced  contraction  of  the  sphincter  of  the  eyelids,  in 
consequence  of  a  fleshy  slip  being  prolonged  from  the  orbicularis  to  the 
special  elevator. 


INTERNAL  MAXILLARY  ARTERY. 


Two  of  the  terminal  branches  of  the  internal  maxillary  artery  at  the 
spheno-maxillary  fossa  are  traced  out  in  the  dissection. 


a.  Internal  maxillary  artery. 
h.  Posterior  dental  branch. 

c.  Infra-orbital  branch. 

d.  Buccal  branch. 

e.  Internal    carotid    artery    in   the 

skull. 


/.  Ophthalmic  artery. 

g.  External  carotid  trunk. 

h.  Superficial  temporal  branch. 

n.  Transverse  facial  branch. 


The  posterior  dental  artery,  b,  springing  from  the  internal  maxillary 
near  the  spheno-maxillary  fossa,  is  inclined  downwards  and  forwards  over 
the  upper  maxilla  to  the  front  of  the  bone,  and  anastomoses  with  the 
infra-orbital  artery. 

It  supplies  superficial  and  deep  branches: — the  former  descend  to  the 
buccinator  muscle,  the  periosteum,  and  the  gums;  and  the  latter  enter 
foramina  in  the  bone,  and  supply  offsets  to  the  fangs  of  the  teeth  and  to 
the  lining  membrane  of  the  antrum  maxillare. 

The  infra-orUtal  artery,  c,  arises  near  the  preceding,  and  enters  the 
infra-orbital  canal  with  the  upper  maxillary  nerve.  Continued  through 
that  canal,  it  issues  at  the  infra-orbital  foramen,  and  ends  in  branches  for 
the  lower  eyelid  and  the  parts  between  the  orbit  and  mouth:  it  communi- 
cates with  the  facial,  transverse  facial,  and  posterior  dental  arteries. 

Many  small  offsets  are  furnished  to  the  orbit;  and  near  the  front  of 
the  jaw  bone  it  sends  downwards  an  anterior  dental  branch,  with  a  nerve, 
8,  of  the  same  name,  to  supply  the  incisor  and  canine  teeth. 

The  transvere  facial  artery,  n,  commonly  a  branch  of  the  superficial 


U,PPER    MAXILLARY    NERVE. 


179 


temporal,  crosses  the  side  of  the  face,  sui^plying  the  contiguous  parts,  and 
anastomoses  with  the  facial  and  the  infra-orbital  arteries. 


UPPER  MAXILLARY  NERVE. 

The  second  trunk  of  the  fifth  cz*anial  nerve  (p.  107)  is  named  as  above 
from  passing  through  the  upper  maxilla;  it  supplies  the  teeth  of  the 
upper  jaw. 


1.  Posterior  dental  branch. 

2.  Upper  maxillary  nerve. 

3.  Optic  nerve. 

4.  Orbital  branch,  cut. 

5.  Ophthalmic  trunk. 


6.  Inferior  maxillary  trunk. 

7.  Buccal  branch. 

8.  Anterior  dental  branch. 

9.  Branches  of  the  facial  nerve. 


The  upper  maxillary  nerve,  2,  leaves  the  skull  by  the  foramen  rotun- 
dum,  and  courses  to  the  face  across  the  spheno-maxillary  fossa,  and 
through  the  infra-orbital  canal.  In  the  face  it  splits  into  large  branches 
which  are  distributed  to  the  muscles  and  the  integuments  between  the 
eye  and  the  mouth:  a  fine  offset  ascends  with  a  small  artery  to  the  lower 
eyelid  and  the  orbicular  muscle.  Its  facial  or  terminal  branches  join  in 
a  plexiform  manner  with  branches  of  the  facial  nerve.  It  gives  off  the 
folic  wing  branches: — 

Dental  branches : — These  are  usually  two  in  number,  one  at  the  back, 
and  the  other  at  the  front  of  the  maxilla. 

The  posterior  branch,  1,  descends  on  the  jaw,  gradually  diminishing 
in  size,  and  is  received  into  a  canal  in  the  bone.  Most  of  its  branches 
course  through  the  bone  to  supply  the  grinding  teeth,  but  one  or  two 
slender  offsets  are  furnished  to  the  gums  and  the  buccinator  muscle. 

The  anterior  branch,  8,  is  conducted  by  a  bony  canal  in  front  of  the 
antrum  to  the  bicuspid  and  incisor  teeth:  it  sends  some  filaments  to  the 
mucous  lining  of  the  nose,  and  joins  the  posterior  branch. 

Orlital  and  spheno -palatine  branches: — Opposite  the  spheno-maxillary 
fossa  these  remaining  branches  take  origin. 

The  orbital  branch,  4  (temporo-malar),  is  a  cutaneous  nerve  of  the 
face  and  temple,  and  receives  its  designation  from  passing  through  the 
cavity  of  the  orbit.  In  the  dissection  it  was  cut  necessarily  by  the 
removal  of  the  outer  wall  of  the  orbit.  In  its  uninjured  state  the  nerve 
can  be  traced  into  the  orbit,  where  it  splits  into  a  temporal  and  a  malar 


180  ILLUSTRATIONS    OF    DISSECTIONS 

branch;  these  issue  to  their  destination  through  apertures  in  the  malar 
bone. 

The  spheno-palatine  brandies,  two  in  number,  descend  beneatli  the 
internal  maxillary  artery,  and  communicating  with  Meckel's  ganglion  in 
the  spheno-maxillary  fossa,  supply  the  lining  membrane  of  the  nose  and 
roof  of  the  mouth;  the  soft  palate,  and  the  tonsil;  and  the  mucous  lining 
of  the  pharynx  near  the  aperture  of  tlie  Eustachian  tube. 

The  upper  maxillary  trunk  of  the  fifth  nerve  springs  from  the  Gasse- 
rian  ganglion  without  commixture  witli  tlie  motor  root,  and  is  solely  a 
sensory  nerve,  like  the  first  or  ophthalmic  trunk.  To  its  influence  is  due 
the  sensibility  of  a  part  of  the  face,  of  the  teeth  of  the. upper  jaAv,  of  the 
nose  cavity,  and  of  the  roof  of  the  mouth  and  the  soft  palate. 

Facial  nerve. — This  branch,  of  rather  large  size,  which  is  marked  Avith 
9,  is  called  infra-orbital:  it  lies  below  the  orbit,  and  supplies  the  muscles 
between  the  eye  and  mouth,  and  on  the  nose.  In  its  course  inwards  its 
offsets  cross,  and  join  the  branches  of  the  upper  maxillary  nerve,  forming 
the  infra-orbital  plexus  by  this  arrangement. 

The  facial  is  the  motor  nerve  chiefly  of  the  muscles  of  the  face  and 
head;  and  it  is  distributed  for  the  most  part  to  muscles  receiving  sensi- 
bility from  the  three  trunks  of  the  fifth  cranial  nerve.  To  the  buccinator, 
which  acts  as  a  muscle  of  mastication  as  well  as  a  dilator  of  the  aperture 
of  the  mouth,  it  gives  the  ability  to  contract;  and  consequently  this 
muscle  is  paralyzed  when  the  other  muscles  which  are  supplied  by  the 
facial  nerve  lose  their  contractile  power. 


DESCRIPTION^  OF  PLATE  XXIV. 


This  Illustration  will  serve  as  a  guide  to  the  dissection  of  the  internal 
carotid  and  ascending  pharyngeal  arteries,  and  of  the  cranial  nerves  dis- 
tributed in  the  neck. 

After  the  examination  of  the  pterygoid  region  and  the  upper  maxil- 
lary nerve,  the  dissection  delineated  will  be  prepared  by  detaching  the 
styloid  process  with  its  muscles,  and  the  external  carotid  artery  and  its 
branches;  and  by  sawing  off  the  large  piece  of  the  side  of  the  skull  out- 


PLATE  XXIV. 


H  Beiicke.IH1> 


DEEP    MUSCLES    OF    THE    NECK. 


181 


side  the  jugular  foramen  and  the  carotid  canal.  Finally  a  dense  fibrous 
tissue  surrounding  the  nerves  and  vessels  near  the  base  of  the  skull  should 
be  taken  away  carefully;  and  as  the  internal  jugular  vein  renders  obscure 
the  view  of  many  objects  it  may  be  removed. 


DEEP  MUSCLES  OF  THE  NECK. 

Lying  on  the  front  of  the  spinal  column  are  the  deep  muscles  for  the 
flexion  and  rotation  of  this  part  of  the  spine,  and  of  the  head,  which  will 
be  now  described.  And  superficial  to  the  level  of  the  carotid  bloodvessels 
is  the  group  of  muscles,  before  referred  to  in  part,  which  belongs  to  the 
pharynx  and  tongue,  and  the  hyoid  bone  and  the  larynx. 


A. 

Scalenus  anticus. 

P. 

Tliyro-hyoideus. 

B. 

Scalenus  medius. 

Q. 

Hyo-glossus. 

C. 

Sterno-mastoicleus. 

R. 

Constrictor  inferior. 

D. 

Splenius  capitis,  cut. 

S. 

Constrictor  medius. 

E. 

Levator  anguli  scapulae. 

T. 

Submaxillary  gland. 

F. 

Obliquus  capitis  inferior. 

U. 

Styloid  process,  cut  oflt. 

G. 

Obliquus  capitis  superior. 

V. 

Stylo-glossus. 

H. 

Rectus  capitis  lateralis. 

W. 

Stylo-pharyngeus. 

I. 

Pterygo-maxillary  ligament. 

X. 

Constrictor  superior. 

J. 

Rectus  capitis  anticus  major. 

X'. 

Buccinator. 

K. 

Longus  colli. 

Y. 

Levator  palati, 

L. 

Sterno-hyoideus. 

Z. 

Tensor  palati. 

M. 

Sterno-thyroideus. 

X 

Cartilage     of     the     Eustachi 

N. 

Thyroid  body. 

tube. 

O. 

Omo-hyoideus. 

The  rectus  capitis  lateralis,  H,  resembles  in  position  an  inter-trans- 
verse muscle;  it  is  attached  below  to  the  lateral  part  of  the  atlas,  and 
above  to  the  jugular  eminence  of  the  occipital  bone. 

The  muscle  will  approximate  the  skull  to  the  atlas,  and  so  help  in 
inclining  the  head  towards  the  shoulder. 

The  rectus  cajjitis  anticus  major,  J,  is  continued  upwards  in  a  line  with 
the  anterior  scalenus.  Arising  below  where  the  scalenus  is  attached,  viz., 
from  the  transverse  processes  of  the  6th,  5th,  4th,  and  3d  cervical  verte- 
bras, it  ascends,  becoming  thicker  near  the  skull,  to  be  inserted  into  the 
basilar  process  of  the  occipital  bone. 

If  the  muscles  of  opposite  sides  act  the  head  will  be  bowed  forwards; 


182 


ILLCSTEATIONS    OF   DISSECTIONS. 


but  only  one  acting  it  will  turn  the  face  to  its  own  side,  in  consequence 
of  its  oblique  position. 

A  third  rectus  muscle  (rect.  cap.  anticus  minor)  lies  between  the  two 
jorecedmg,  and  passes  from  the  atlas  to  the  basilar  process  of  the  occipital 
bone;  it  is  concealed  by  the  vessels  and  nerves  near  the  head. 

The  longus  colli  muscle,  K,  lies  on  the  front  of  the  spinal  column, 
between  the  atlas  and  the  second  dorsal  vertebra;  and  it  is  attached  to 
the  bodies  of  the  vertebrge  and  to  certain  of  the  transverse  processes. 
For  the  complete  display  of  the  muscle  the  pharynx  should  be  detached. 

The  muscle  bends  forwards  the  spine,  and  can  rotate  the  same  by 
means  of  the  lateral  slips  connected  with  the  transverse  processes  of  the 
vertebrae. 


SUBCLAVIAN  AND  CAEOTID  ARTERIES. 

In  this  Illustration  the  internal  carotid  artery  can  be  observed 
throughout;  and  by  means  of  the  Figure  a  more  complete  view  of  some 
of  the  branches  of  the  subclavian  and  carotid  trunks  may  be  obtained. 


a.  Subclavian  trunk. 
6.  Vertebral  artery. 

c.  Internal  mammary  branch. 

d.  Thyroid  axis. 

e.  Inferior  thyroid  artery. 
/.  Supra-scapular  artery. 

g.  Transverse  cervical  artery. 
h.  Ascending  cervical  branch. 
i.    Common  carotid  trunk. 
k.  Upper  thyroid  artery. 
I.    Crico-thyroid  branch, 
m.  External  carotid  trunk. 


n.  Laryngeal  branch. 
o.  Lingual  artery. 
p.  Facial  artery. 

q.  Occipital    artery,    cut ;     with 
branch  to  stemo-mastoideus. 
r,  Tonsillitic  branch, 
s.  Inferior  palatine  branch. 
t.   Ascending  pharyngeal  artery. 
u.  Internal  carotid  trunk. 
X.  Internal  maxillary  artery,  cut. 
y.  Internal  jugular  vein,  cut. 


Suhclavicm  trunk . — The  arch  of  the  subclavian  artery,  and  the 
branches  of  its  first  part  (p.  154)  are  here  rej)resented. 

In  this  body  a  rare  condition  of  the  inferior  thyroid  artery,  e, 
existed;*  the  vessel  sprang  from  the  vertebral  artery,  h,  instead  of  the 
thyroid  axis,  d,  and  then  took  its  usual  course  to  the  thyroid  body,  N. 


*  In  Mr.  Quain's  Surgical  Anatomy  of  the  Arteries,  p.  169,  it  is  said  to  have 
been  seen  once. 


SUBCLAVIAN    AND    CAROTID    ARTERIES.  183 

CoDunon  carotid  artery,  i. — The  extent  and  situation  of  the  artery, 
and  the  nerves  in  connection  with  it  (p.  146)  can  be  well  perceived  in  this 
Plate.  In  this  body  the  arterial  trunk  splits  into  two  at  a  point  higher 
than  usual. 

External  carotid  trunk,  m. — Only  the  lower  part  of  the  artery,  with 
its  first  branches  wdiich  were  not  represented  or  only  imperfectly  in  pre- 
ceding Plates,  has  been  left  in  the  dissection.  And  as  the  carotid  begins 
above  the  usual  place  these  first  branches  have  to  descend  to  their 
destined  positions. 

The  dipper  thyroid,  Jc,  runs  over  the  superficial  surface  of  the  thyroid 
body,  N,  before  entering  the  substance.  It  furnishes,  firstly,  muscular 
offsets;  next  a  lar}Tigeal  branch,  n  ;  and  lastly,  a  crico-thyroid  branch,  I, 
W'hich  lies  on  the  membrane  of  the  same  name,  joining  that  of  the  oppo- 
site side,  and  would  be  endangered  in  the  operation  of  laryngotomy. 

Lingual  artery,  o : — its  hyoidean  offset  arises  before  the  artery  passes 
beneath  the  hyo-glossus,  Q,  and  is  distributed  to  the  thyro-hyoideus,  P. 

The  facial  artery,  p,  furnishes  the  following  branches  to  the  neck 
before  it  reaches  the  jaw: — 

A  tonsillitic  offset,  r,  ascends  between  the  pterygoideus  internus  and 
the  stylo-giossus,  V,  and  perforating  the  upper  constrictor,  X,  ends  in 
the  tonsil  and  the  side  of  the  tongue. 

An  inferior  palatine  branch,  s,  courses  along  the  side  of  the  pharynx 
between  the  stylo-glossus  and  stylo-pharyngeus  muscles  to  the  upper 
border  of  the  superior  constrictor,  X,  -where  it  passes  inwards  to  supply 
the  palate.  It  supplies  muscular  branches;  and  one  offset,  long  and 
slender,  reaches  the  Eustachian  tube  J. 

Other  offsets  of  the  facial,  viz.,  submental  and  glandular  are  seen  in 
Plate  xvii. 

The  ascending  ^iharyngeal  artery,  arises  near  the  beginning  of  the 
external  carotid,  and  ascends  on  the  spinal  column  between  the  pharynx 
and  the  internal  carotid  trunk  nearly  to  the  skull.  Here  it  enters  the 
pharynx  above  the  upjDer  constrictor,  and  ends  in  branches  to  the  front 
and  back  of  the  soft  palate;  of  these  the  anterior  are  the  largest,  and  join 
with  corresponding  branched  of  the  opposite  side,  so  as  to  form  two  arches 
beneath  the  mucous  membrane — one  lying  near  the  uppei",  and  the  other 
near  the  lower  edge  of  the  velum  palati  (Quain).* 

*  Fifth  edition  of  Quain's  Anatomy,  1846,  p.  489. 


184 


ILLUSTRATIONS    OF    DISSECTIONS. 


Branches  are  given  to  tl:e  contiguous  muscles,  the  lymphatic  glands, 
and  the  nerves;  and  one  (meningeal)  enters  the  skull  through  the  fora- 
men lacerum,  and  ends  in  the  dura  mater. 

The  internal  carotid  artery,  it,  ascends  through  the  neck  and  the 
temporal  bone  to  the  interior  of  the  cranium,  and  terminates  in  branches' 
for  the  brain  and  the  orbit. 

The  cervical  part  of  the  vessel,  of  the  same  size  throughout  and  devoid 
of  branches,  lies  by  the  side  of  the  pharynx,  and  rests  on  the  rectus  anti- 
cus,  J.  At  first  the  artery  is  accessible  in  an  operation  (p.  148),  but  it 
becomes  deep  afterwards  beneath  the  parotid  gland  and  the  digastricus, 
and  the  styloid  i^rocess  and  its  muscles. 

The  internal  jugular  vein  is  contained  in  a  sheath  of  fascia  vv^ith  the 
artery,  and  is  external  or  posterior  to  it. 

ISTumerous  nerves  are  in  contact  with  the  vessel.  Crossing  it  super- 
ficially from  above  down  are  the  glosso-pharyngeal,  1,  the  pharyngeal 
branch  of  the  vagus,  5,  and  the  hypoglossal  nerve,  7;  and  beneath  it,  also 
with  a  cross  direction,  are  the  pharyngeal  branches  of  the  sympathetic, 
the  upper  laryngeal,  3,  and  the  external  laryngeal,  4.  In  the  sheath 
between  it  and  the  vein,  and  parallel  to  it,  lies  the  vagus  nerve,  2;  and 
behind  the  sheath  and  parallel,  is  placed  the  sympathetic  nerve  with  its 
branches.  Close  to  the  skull  the  cranial  nerves  issuing  by  the  foramen 
jugulare  and  anterior  condyloid  foramen  interpose  between  the  artery 
and  vein,  but  they  diverge  afterwards  to  their  destination. 

In  the  temporal  bone  the  artery  becomes  flexuous,  and  fills  the  carotid 
canal,  only  a  few  branches  of  the  sympathetic  ascendmg  around  it:  here 
it  gives  a  small  tympanic  branch  to  the  ear,  which  pierces  the  bone. 

For  the  anatomy  of  the  artery  in  the  skull  see  Plate  xiii.  (p.  109); 
and  for  the  description  of  the  ophthalmic  artery  refer  to  p.  113. 


DEEP  NERVES  OF  THE  NECK. 

Four  cranial  nerves,  and  the  sympathetic  nerve,  with  their  branches, 
to"-ether  with  the  spinal  nerves  of  the  neck,  are  visible  in  the  Plate. 


1.  Glosso-pharyngeal  nerve. 

2.  Vagus  nerve. 

3.  Upper  laryngeal  nerve. 

4.  External  laryngeal  nerve. 


5.  Pharyngeal  branch. 

6.  Spinal  accessory  nerve. 

7.  Hypoglossal  nerve. 

8.  Descendens  noni  branch. 


■  DEEP    NERVES    OF   THE    NECK. 


185 


9.  Communicating  branch  from  the 
spinal  nerves. 

10.  Recurrent  laryngeal  nerve. 

11.  Cord  of  the  sympathetic  ners^e. 

12.  Upper  cervical  ganglion. 

13.  Middle  cervical  ganglion. 

14.  Lower  cervical  ganglion. 

15.  Middle  cardiac  nerve. 

16.  First  cervical  nerve  (loop  of  the 

atlas). 

17.  Second  cervical  nerve. 

18.  Third  cervical  nerve. 

19.  Fourth  cervical  nerve. 


20.  Phrenic  nerve. 

21.  Fifth  cervical  nerve. 

22.  Sixth  cervical  nerve. 

23.  Seventh  cervical  nerve. 

24.  Eighth  cervical  nerve. 

25.  Supra-scapular  nerve. 

26.  Carotid  branches  of  the  sympa- 

thetic. 

27.  Upper  maxillary  nerve. 

28.  Optic  nei've. 

ft    Cardiac  branches  of  the  vagus  in 
the  neck. 


The  glosso-pharyngeal  or  ninth  cranial  nerve,  1,  leaves  the  skull  by 
the  jugular  foramen,  and  courses  to  the  pharynx  over  the  carotid  artery; 
passing  then  beneath  the  hyo-glossus  muscle,  Q,  it  ends  in  terminal 
branches  for  the  tongue.  In  the  foramen  of  exit  the  nerve  possesses  two 
small  ganglia,  and  furnishes  a  branch  (Jacobson's  nerve)  to  the  tym- 
panum.    Its  branches  beyond  the  cranium  are  the  following: — 

As  it  crosses  the  carotid  artery  some  fine  filaments  descend  on  the 
vessel,  and  join  the  sympathetic  and  the  pharyngeal  branch,  5,  of  the 
vagus. 

Muscular  branches  enter  the  stylo-pharyngeus  and  the  upper  two 
constrictors;  and  at  the  side  of  the  pharynx  it  joins  in  a  plexus  (pharyn- 
geal) with  offsets  of  the  sympathetic  and  of  the  pharyngeal  branch  of  the 
vagus. 

Numerous  offsets  are  distributed  to  the  mucous  membrane  of  the 
pharynx  opposite  the  opening  of  the  mouth. 

The  nerve  is  chiefly  sensory  in  its  function,  and  it  confers  on  a  part  of 
the  tongue  the  faculty  of  tasting  as  before  said  (p.  176);  but  as  the  stylo- 
pharyngeus  muscle  is  supplied  altogether  by  it  some  motor  influence 
must  be  obtained  from  it.  By  means  of  its  branches  to  the  lining  of  the 
pharynx  impressions  produced  by  the  presence  of  food  are  conveyed  to 
the  sensorium. 

The  pneumo-gastric,  vagus,  or  tenth  cranial  nerve,  2,  issues  from  the 
skull  by  the  foramen  jugulare.  In  the  aperture  of  exit  it  has  a  ganglion 
(gang,  of  the  root);  and  it  gives  a  branch  to  the  ear,  like  the  glosso- 
pharyngeal. 

Beyond  the  skull  it  is  continued  through  the  neck  to  the  thorax,  lying 


186  ILLUSTRATIONS    OF    DISSECTIONS. 

in  the  carotid  sheath  between  the  artery  and  the  jugular  vein;  and  as  it 
leaves  the  neck  on  the  right  side  it  crosses  the  subclavian  artery.  Kear 
the  skull  it  is  marked  by  a  long  fusiform  ganglion  (gang,  of  the  trunk), 
,  which  is  united  with  the  hypoglossal  nerve,  7.  In  the  neck  the  nerve 
suiDplies  the  undermentioned  branches  to  the  pharynx,  the  larynx,  and 
the  heart. 

The  i^liaryngeal  branch,  5,  begins  in  the  ganglion,  and  crosses  over 
(sometimes  under)  the  internal  carotid,  to  reach  the  pharynx.  After 
being  joined  by  offsets  of  the  glosso-pharyngeal,  it  communicates  with 
the  sympathetic  and  the  superior  laryngeal  to  form  the  pharyngeal  plexus: 
it  ends  in  the  constrictor  muscles. 

The  upper  laryngeal  nerve,  3,  arises  also  from  the  ganglion,  and 
courses  under  the  carotid  to  the  interval  between  the  hyoid  bone  and  the 
thyroid  cartilage:  here  it  pierces  with  an  artery  the  thyro-hyoid  ligament, 
and  is  distributed  to  the  mucous  membrane  of  the  larynx.  See  Plate  of 
the  larynx. 

Under  the  carotid  it  joins  largely  with  the  sympathetic  nerve;  and  it 
furnishes  the  external  laryngeal  nerve,  4,  which  supplies  the  inferior  con- 
strictor, and  ends  in  the  crico-thyroideus  muscle  (Plate  xxv.). 

Cardiac  branches,  \  f.  One  springs  from  the  nerve  trunk  at  the 
lower,  and  one  or  two  at  the  upper  part  of  the  neck:  they  join  branches 
of  the  sympathetic.  In  this  dissection  the  upper  communicated  with  the 
descendens  noni  nerve. 

Recurrent  or  inferior  laryngeal  nerve,  10.  On  the  right  side  this 
nerve  arises  as  the  vagus  enters  the  thorax,  and  winding  round  the  sub- 
clavian artery,  runs  back  to  the  larynx:  it  is  distributed  chiefly  to  the 
laryngeal  muscles.  See  Plate  xxvii.  On  the  left  side  the  nerve  begins 
in  the  thorax  opj)osite  the  arch  of  the  aorta,  round  which  it  makes  a  loop 
to  come  back  to  the  larynx. 

In  the  neck  the  pneumo-gastric  nerve  ramifies  in  the  walls  of  the  air 
and  food  passages,  and  bestows  sensibility  on  the  mucous  membrane  and 
contractility  on  the  muscular  structure;  but  the  contraction  of  the  muscles 
supplied  not  being  placed  under  the  control  of  the  will  (except  those  of 
voice),  the  nerve  resembles  more  the  sympathetic  than  the  other  motor 
cranial  nerves. 

From  the  partial  mixing  of  its  motor  and  sensory  nerve  fibres  the 
branches  in  the  neck  have  difEerent  functions.  Experiments  seem  to  de- 
termine that  the  pharyngeal  branch  is  a  motor  nerve;  the  superior  laryn- 


THE   SYMPATHETIC   NERVE.  187 

geal,  chiefly  sensory;  and  the  recurrent  hiryngeal  a  motor  nerve  of  the 
muscles  of  the  hirynx,  but  invokmtary  motory,  and  sensory  to  the  muscular 
fibres  in  the  trachea.  The  small  cardiac  branches  are  probably  involun- 
tary motory,  and  sensory  in  function  like  those  to  the  lung. 

The  spinal  accessory  or  eleventh  cranial  nerve,  6,  comes  out  of  the 
skull  by  the  foramen  jugulare,  and  communicates  in  that  aperture  with 
the  vagus  by  means  of  an  accessory  piece. 

Beyond  the  foramen  the  nerve  is  directed  downwards  and  backwards 
to  the  sterno-mastoideus,  which  it  pierces,  and  to  the  Trapezius  muscle 
(Plate  XV.  p.  134).  It  joins  freely  with  branches  of  the  cervical  j)lexus, 
and  supplies  with  them  the  two  muscles  named. 

This  nerve  resembles  a  spinal  nerve  in  arising  from  the  spinal  cord, 
and  in  being  moto-sensory  in  function;  and  this  double  function  is  not 
altogether  dependent  upon  its  union  with  the  spinal  nerves,  for  it  alone 
may  supply  the  sterno-mastoideus. 

The  hypoglossal,  or  twelfth  cranial  nerve,  7,  leaves  the  skull  by  the 
anterior  condyloid  foramen,  and  turning  over  the  vagus,  with  which  it  is 
inseparably  united,  descends  as  low  as  the  digastric  muscle  before  it  is 
directed  forwards  to  the  tongue.  No  offset  is  distributed  from  the  first 
part  of  the  nerve,  though  it  joins  the  vagus,  the  sympathetic,  and  the 
first  spinal  nerve;  but  many  muscular  branches  arise  from  the  last  part 
of  the  hypoglossal,  as  may  be  seen  in  Plate  xxiii. 

It  is  supposed  to  be  altogether  a  motor  nerve  at  its  origin;  and  it  is 
thought  that  any  sensory  influence  possessed  by  it  is  derived  from  its  junc- 
tion with  other  nerves  near  the  skull. 

Sympathetic  nerve. — The  cervical  part  of  the  sympathetic  nerve,  11, 
lies  on  the  spine  beneath  the  great  bloodvessels,  and  is  continuous  witl] 
the  knotted  cord  in  the  thorax.  In  the  neck  it  is  marked  by  three  gang« 
lia — upper,  middle  and  lower;  and  each  ganglion  furnishes  external  or 
communicating  branches,  internal  or  visceral,  and  branches  to  blood- 
vessels. 

The  upper  ganglion,  12,  is  the  largest  of  the  three:  it  is  fusiform  in 
shape,  with  a  reddish  color,  and  is  about  two  inches  long.  Near  the  base 
of  the  skull  the  cranial  nerves  lie  over  it. 

The  outer  branches  communicate  with  the  first  four  spinal  nerves, 
and  with  the  tenth  and  twelfth  cranial  nerves. 

Most  of  the  inner  branches  pass  beneath  the  carotid  to  join  in  the 


188  ILLUSTRATIONS    OF   DISSECTIONS. 

pharyngeal  plexus;  but  one,  larger  than  the  rest  and  named  upper  car- 
diac, descends  beneath  the  artery  to  the  cardiac  plexus  in  the  thorax. 

The  nerves  to  bloodvessels  from  the  ganglion  (nervi  molles)  ramify  on 
both  carotid  arteries,  forming  plexuses  on  them;  and  on  some  of  the 
branches  of  the  external  carotid  there  are  interspersed  ganglia.  Through 
the  offset,  26,  on  the  internal  carotid  the  vessels  and  the  vascular  mem- 
brane of  the  brain  are  supplied,  and  communications  take  place  with  the 
cranial  nerves  in  the  middle  fossa  of  the  base  of  the  skull. 

The  middle  ganglion,  13,  variable  in  size  and  shape,  is  placed  near  the 
inferior  thyroid  artery,  e,  and  is  smaller  than  the  others.  Its  offsets  are 
the  following: — 

Outer  branches  which  join  usually  the  fiftli  and  sixth  spinal  nerves. 

Inner  branches  ramify  on  the  thyroid  artery  and  end  in  the  thyroid 
body.  One  of  these,  the  middle  cardiac  nerve,  15,  is  continued  to  the 
cardiac  plexus  in  the  tliorax. 

The  inferior  ganglion  lies  beneath  the  subclavian  artery  and  close 
above  the  neck  of  the  first  rib.  It  is  rather  rounded  in  shape,  and  is 
often  divided  into  parts,  as  in  the  Figure,  where  one  of  the  pieces  is 
marked,  14.     Its  branches  are  similar  to  those  of  the  other  ganglia. 

Outer  branches,  two  or  more  in  number,  join  tlie  two  lowest  cervical 
nerves. 

One  large  inner  or  visceral  branch,  inferior  cardiac,  runs  beneath  the 
subclavian  artery  to  the  cardiac  plexus  in  the  thorax. 

Offsets  to  the  bloodvessels  entwine  around  the  vertebral  artery,  h, 
forming  a  plexus  on  it;  and  other  nerves  ramify  on  the  subclavian  trunk 
which  they  surround  with  one  or  two  loops. 

Tlie  branches  of  the  sympathetic  in  the  neck  serve  chiefly  to  connect 
this  nerve  with  others,  and  to  supply  the  bloodvessels. 

By  means  of  the  communicating  branches  with  the  cranial  and  spinal 
nerves  the  sympathetic  gives  fibres  to,  and  receives  fibres  from  those 
nerves;  and  the  offsets  joining  the  anterior  primary  trunk  of  each  spinal 
nerve  are  directed  through  the  roots  of  the  nerve  towards  the  spinal  cord, 
and  send  also  some  fibres  to  the  trunk  of  the  nerve  to  be  distributed  pe- 
ripherally with  it. 

To  the  bloodvessels  the  sympathetic  gives  the  power  of  regulating  the 
quantity  of  blood  circulating  through  them;  so  that  on  section  of  its 
nerves  (vaso-motory)  to  them  the  muscular  coat  is  paralyzed,  and  being 
unable  to  contract  on  the  contained  fluid,  the  blood  slackens  in  speed, 


SPINAL    NERVES    OF   THE    NECK.  1S9 

and  congestion  of  the  vessels  of  the  part  and  increased  heat  ensue. 
Stimulating  the  cut  nerves  by  galvanism  will  restore  for  the  time  con- 
traction of  the  muscular  coat,  and  will  cause  a  decrease  in  the  congestion 
and  the  heat. 

Spinal  nerves. — Eight  in  number,  they  are  divided  equally  between 
two  plexuses; — the  upper  four  entering  the  cervical,  and  the  lower  four 
the  brachial  plexus. 

Cervical  j^^&^us. — The  anterior  jorimary  branches  of  the  first  four 
nerves  interlace  in  the  cervical  plexus:  they  are  marked  16  to  19  inclu- 
sive, and  the  small  branch  of  the  first,  IG,  is  named  tho  loop  of  the  atlas. 
The  superficial  offsets  of  the  plexus  are  delineated  in  Plate  xv. ;  the  deep 
branches  follow  below: — 

Brandies  io  muscles. — From  the  loop  between  the  first  two  nerves 
branches  arc  furnished  to  the  contiguous  recti  muscles;  and  from  the 
other  loops  of  the  plexus  the  surrounding  muscles,  viz.,  the  sterno-mas- 
toideus  C,  Levator  anguli  scapulae  E,  scalenus  medius  B,  intertransver- 
sales,  trapezius,  and  the  platysma,  receive  nerves. 

Communicating  hranclies. — Offsets  unite  the  loop  of  the  atlas  with  the 
vagus  and  hypoglossal  nerves,  2  and  7,  and  with  the  upper  ganglion  of 
the  sympathetic,  13.  And  two  small  branches  from  the  second  and  third 
nerves,  17  and  18  (in  this  case  one  comes  also  from  the  fourth  nerve,  19) 
join  in  one,  9,  which  unites  with  the  descendens  noni,  and  assists  to  sup- 
ply the  depressor  muscles  of  the  hyoid  bone. 

The  diaijhragmatic  or  phr one  nerve,  20,  begins  in  the  fourth  cervical 
nerve,  but  it  often  joins  the  trunk  of  the  fifth  nerve,  21,  as  it  passes  by. 
Jt  descends  to  the  thorax  over  the  scalenus  anticus  A,  and  inside  the  in- 
ternal mammary  artery,  c,  as  in  the  Drawing. 

Brachial  plexus. — The  lower  four  nerves  are  much  larger  than  the 
upper,  and  are  prolonged  to  the  upper  limb.  The  ti'unks,  marked  from 
21  to  24  inclusive,  issue  between  the  anterior  and  the  middle  scalenus,* 
an-d  join  with  part  of  the  first  dorsal  in  the  large  cords  seen  in  the  Figure. 
Only  two  of  the  branches  arising  from  the  plexus  above  the  clavicle 
are  now  visible,  viz.,  the  supra-scapular  25,  and  the  small  nerve  to  the 
subclavius;  the  rest  of  this  set  of  branches  are  shown  in  Plate  xv.  (p.  134). 

*  In  this  body  the  fifth  and  the  fovirth  cervical  came  in  front  of  the  anterior 
scalenus. 


190 


ILLUSTKATIOKS    OF    DISSECTIOWSo 


DESCRIPTION  OF  PLATE  XXV. 


A  SIDE  view  of  the  pharynx  with  its  muscles  is  depicted  in  this  Fi^ire. 

Por  this. dissection  the  base  of  the  skull  is  to  be  cut  through  behind 
the  attachment  of  the  pharynx;  and  the  fore  part  of  the  head  being  fixed 
on  a  ?jlock,  and  the  pharynx  distended  with  tow,  the  muscles  will  be 
easily  prepared. 


THE  PHAEYNX  AND  ITS  ^MUSCLES. 

The  pharynx  is  the  upper  part  of  the  alimentary  tube  which  is  placed 
behind  the  nose,  mouth,  and  larynx.  Both  the  food  and  air  pass  along 
it.  It  reaches  from  the  skull  to  the  lower  end  of  the  larynx,  gradually 
tapering  from  above  down,  and  measures  from  five  to  six  inches  in  length. 
Above  it  is  inserted  into  the  skull  by  a  thin  fibrous  membrane  called  the 
aponeurosis  of  attachment  of  the  pharynx;  and  in  front  it  is  fixed  to  the 
head,  the  hyoid  bone,  and  the  larynx. 

In  the  wall  of  the  pharynx  are  contained  constricting  and  elevating 
muscles,  which  are  employed  in  swallowing;  the  latter  are  engaged  in 
placing  the  receiving  bag  in  the  position  required  for  the  entrance  of  the 
food  or  drink,  and  the  former  urge  onwards  to  the  gullet  the  morsel  re- 
ceived. 


A.  Inferior  constrictor. 

B.  Middle  constrictor. 

C.  Superior  constrictor. 

D.  Stylo-pharyngeus. 

E.  Levator  palati. 

F.  Tensor  palati. 

G.  Buccinator. 

H.  Stylo-glossus,  cut. 

I.  Tenaporal  muscle. 

J.  Mylo-hyoideus. 
K.  Stemo-hyoideus. 


L.  Omo-hyoideus. 

M.  Hyo-glossus. 

N.  Thyro-hyoideus. 

O.  Stylo-hyoid  ligament,  ossified. 

P.  Stemo-thyroideus. 

Q.  Crico-thyroideus. 

R.  Thyroid  body,  thrown  down. 

S.  CEsophagus  or  gullet. 
T.  Trachea  or  windpipe. 

f  Pterygo-raaxillary  ligament. 


PLATE  XXV. 


i     " 


"X. 


THE   PHARYNX    AND    ITS    MUSCLES.  191 

The  constrictor'  muscles  arc  flat  and  thin,  and  are  three  in  number  on 
each  side,  viz.,  lower,  middle,  and  upper.  They  are  attached  in  front  to 
the  larynx,  hyoid  bone,  and  the  head,  and  meet  their  fellows  in  the  mid- 
dle line  behind:  their  contiguous  edges  overlap  like  scales,  the  upper 
being  more  superficial. 

The  loioer  constrictor,  A  (laryngo-pharyngeus),  arises  from  the  side  of 
the  cricoid  and  thyroid  cartilages  of  the  larynx;  and  the  fibres  end  in  the 
middle  line  behind.  Its  upper  edge  overlays  the  middle  constrictor  B, 
and  the  lower  is  continuous  with  the  circular  fibres  of  the  oesophagus. 

The  middle  constrictor,  B  (hyo-pharyngeus),  is  connected  in  front 
with  the  hyoid  bone,  viz.  with  the  great  and  small  cornua,  and  with  the 
lower  end  of  the  stylo-hyoid  ligament,  0.  The  fibres  radiate  to  their 
ending  at  the  middle  line  behind,  the  lower  passing  beneath  the  inferior 
constrictor,  and  the  upper  over  the  superior  constrictor  to  within  an  inch 
of  the  skull. 

The  upper  constrictor,  C  (cephalo-pharyngeus),  is  fixed  by  its  anterior 
edge  to  the  following  parts:  to  the  pterygoid  plate  (lower  third  of  the 
inner  surface)  and  the  hamular  process,  to  the  pterygo-maxillary  ligament, 
f,  to  the  lower  jaw  behind  the  last  molar  tooth,  to  the  mucous  membrane 
of  the  floor  of  the  mouth,  and  to  the  side  of  the  tongue.  As  the  fibres 
pass  back  to  the  middle  line,  the  upper  form  a  free  curved  border  below 
the  skull,  where  the  levator  palati  muscle  E  enters  above  them,  and  the 
lower  are  continued  beneath  the  middle  constrictor,  and  blend  with  fibres 
of  the  stylo-pharyngeus. 

When  these  muscles  contract,  they  diminish  the  size  of  the  pharyngeal 
cavity  by  moving  forwards  the  loose  hinder  part.  In  swallowing,  the  two 
lowest  grasp  and  convey  onwards  by  successive  rapid  contractions  the 
morsel  of  food  or  the  drink;  whilst  the  upper  one,  which  is  placed  above 
the  aperture  of  the  piouth,  takes  little  share  in  the  process,  farther  than 
by  lessening  the  sj)ace  above  the  mouth,  it  so  far  assists  in  opposing  the 
ascent  of  the  food  behind  the  soft  palate.  As  the  tonsil  is  covered  by  the 
upper  constrictor  opposite  the  angle  of  the  lower  jaw,  it  may  be  com- 
pressed during  the  action  of  that  muscle. 

Elevators  of  the  pharynx.  Two  muscles  on  each  side,  an  external 
and  internal  elevator,  descend  from  the  head  to  raise  the  upper  part  of 
the  pharynx  preparatory  to  swallowing. 

The  levator  pharyngis  externus,  D  (stylo-pharyngeus),  arises  from  the 
root  of  the  styloid  process,  and  descends,  becoming  wider,  between  the 


192  ILLUSTRATIONS    OF    DISSECTIONS. 

upper  and  middle  constrictors  to  be  inserted  mainly  into  the  upper  border 
of  the  thyroid  cartilage,  and  in  part  with  the  upper  constrictor  muscle. 

Levator  pharyyigis  internus  (salpingo-pharyngeus)  is  delineated  in 
Plate  xxvi.  N.  It  is  a  small  muscular  slip  inside  the  pharynx,  immedi- 
ately beneath  the  mucous  membrane,  which  arises  by  tendon  from  the  end 
of  the  Eustachian  tube,  0,  and  joins  below  the  palato-pharyngeus  mus- 
cle, 0. 

The  elevators  make  ready  the  pharynx  for  receiving  the  aliment,  and 
they  act  in  this  way: — The  large  elevator  draws  upwards  and  outwards 
the  part  of  the  pharynx  above  the  os  hyoides,  especially  the  part  opposite 
the  opening  of  the  mouth;  and  elevates  the  larynx  at  the  same  time. 
And  the  small  or  internal  elevator  raises  that  part  of  the  pharynx  above 
the  laro-e  elevator,  which  would  become  loose  by  the  action  of  the  other 
muscie. 

Before  deglutition  takes  place  the  hyoid  bone  is  drawn  forwards  and 
upwards  by  its  elevator  muscles,  giving  thus  increased  size  to  the  pharynx 
from  before  back;  and  the  larynx  is  carried  upwards  and  forwards  at  the 
same  time  under  the  tongue,  so  as  t©  allow  the  opening  into  the  wind- 
pipe to  be  placed  in  tbe  position  most  favorable  for  its  closure  during 
the  act  of  swallowing. 


LARYNGEAL  VESSELS. 

Two  arteries  on  each  side  supply  the  larynx,  and  the  pharynx  and 
windpipe  in  part. 


a.  Inferior  thyroid  artery, 
b,. Laryngeal  branch. 
c.  Thyroid  branch. 


d.  Laryngeal    branch  of  the  upper 

thyroid. 

e.  Lingual  artery. 
/.  Internal  carotid. 


The  iqjper  laryngeal  branch,  d,  is  an  offset  of  the  superior  thyroid 
artery,  and  enters  the  larynx  through  the  thyro-hyoid  membrane:  its  dis- 
tribution in  the  larynx  can  be  traced  in  Plate  xxvii. 

The  inferior  thyroid  artery,  a,  ramifies  by  the  branch,  c,  on  the  under 
part  of  the  thyroid  body;  and  sends  a  branch,  h,  into  the  interior  of  the 
larynx,  which  is  delineated  with  the  other  laryngeal  artery. 


PLATE  XX 


%.      ^ 


^^jT{ci&Sif4iS^=?:r?^' 


'■^ 


'\ 


iSfERVES    OF   THE    LARYNX. 


193 


NERVES  OF  THE  LARYNX. 

Three  of  the  nerves  now  apparent  belong  to  the  larynx  and  its  muscles, 
and  the  remaining  three  enter  the  tongue. 


1.  Glosso-pharyngeal  nerve. 

2.  Gustatory  nerve. 

3.  Hypoglossal  nerve. 


4.  Upper  laryngeal  nerve. 

6.  External  laryngeal  nerve. 

7.  Recurrent  laryngeal  nerve. 


The  upper  laryngeal  nerve,  4,  enters  the  larynx  through  the  thyro- 
hyoid membrane  with  the  artery,  and  ends  in  the  mucous  membrane. 

The  external  laryngeal  branch,  6,  arises  from  the  preceding  high  in 
the  neck,  and  is  distributed  outside  the  larynx  to  the  crico-thyroid  mus- 
cle, Q,  and  to  the  inferior  constrictor  A;  and  as  it  is  the  only  nerve 
reaching  that  laryngeal  muscle,  it  must  give  to  the  fibres  sensibility  and 
contractility. 

The  inferior  laryngeal  or  recurrent  nerve,  7,  a  branch  of  the  vagus, 
ascends  between  the  gullet  and  the  windpipe,  and  passes  under  the  in- 
ferior constrictor  to  supply  the  muscles  of  the  larynx  (Plate  xxvii. ).  Mus- 
cular offsets  are  furnished  by  it  to  the  two  tubes  between  which  it  lies. 


DESCRIPTION  OF  PLATE  XXVI. 


The  interior  of  the  pharynx,  and  the  dissection  of  the  muscles  of  the 
soft  palate,  are  comprised  in  this  Illustration. 

The  objects  inside  the  pharynx  will  appear  on  slitting  down  the  tube 
behind,  and  everting  the  edges:  and  the  muscles  of  the  soft  palate  will  be 
laid  bare  by  removing  the  mucous  membrane  on  the  left  side,  and  that 
layer  with  some  muscular  fibres  under  it  on  the  right,  in  the  manner  in- 
dicated. 


13 


194 


ILLUSTRATIONS   OF   DISSECTIONS. 


INTERIOR  OF   THE  PHARYNX. 

The  pharyngeal  cavity  reaches  from  the  base  of  the  skull  to  the  lower 
edge  of  the  cricoid  cartilage  of  the  larynx,  and  tapers  from  above  down. 
At  its  middle  it  serves  as  a  common  passage  for  the  air  and  food,  but  the 
upjDer  part  transmits  air  exclusively,  and  the  lower  part  conveys  only 
food.  These  three  portions,  differing  thus  in  their  use,  have  the  follow- 
ing limits: — the  upper  reaches  as  low  as  the  opening  of  the  mouth,  M, 
and  communicates  with  the  cavities  of  the  nose  and  tympanum;  the 
middle  region  extends  from  the  mouth  to  the  aperture  of  the  larynx  V; 
and  the  third  portion  lies  beyond  the  larynx,  and  is  continuous  below 
with  the  CBSophagus  W.  Along  the  front  of  the  pharynx  are  seven  open- 
ings. 


A.  Tube  of  the  oesophagus. 

B.  Pharynx  cut,  and  reflected. 

C.  Inner  part  of  pharynx  covered 

by  mucous  membrane. 

D.  Septum  nasi. 

E.  Lower  spongy  bone. 

F.  Eustachian  tube. 

I.  Buccinator  muscle. 
K.  Soft  palate. 
M.  Roof  of  the  mouth. 
N.  Salpingo-pharyngeus  muscle. 


O.  The  uvula. 

P.  Anterior  pillar  of  the  palate. 

Q.  The  tonsil. 

R.  Posterior  pillar  of  the  palate. 

S.  The  tongue. 

T.  The  epiglottis. 

v.  Upper  opening  of  the  larynx. 

W.  Opening  of  the  oesophagus. 

X.  Internal  pterygoid  muscle. 

Z.  Mylo-hyoid  muscle. 


The  Eustachian  tube,  F,  one  on  each  side,  lies  close  to  the  base  of 
the  skull;  on  the  right  side  the  mucous  membrane  has  been  removed 
from  the  lower  end.  Its  extremity  in  the  pharynx  is  cartilaginous  and 
membranous,  and  is  dilatable;  but  the  upper  part  is  osseous,  and  is  con- 
tained in  the  temporal  bone.  A't  its  lower  end  the  cartilage  is  enlarged, 
but  more  at  the  inner  than  the  outer  side,  and  gives  to  the  tube  a  funnel- 
shaped  opening.  The  pharyngeal  aperture  is  oval  from  before  back,  and 
is  placed  close  behind  the  internal  pterygoid  plate,  to  which  the  tube  is 
united  by  fibrous  tissue  higher  up;  it  is  on  a  level  with  the  inferior 
meatus,— the  upper  part  of  the  opening  reaching  as  high  as  the  upper 
border  of  the  lower  spongy  bone. 

This  tube  leads  from  the  pharynx  to  the  middle  ear  or  tympanum;  it 


OPENINGS    OF    THE    PHARYNX.  195 

transmits  air  to  the  ear  cavity,  and  allows  the  mucus  of  that  space  to 
escape  through  it.  Ordinarily  the  lower  end  is  closed,  and  the  air  is 
shut  in  tlie  tympanum,  hut  the  j)haryngeal  opening  can  be  rendered 
l^atent  by  the  action  of  the  palate  muscles,  so  as  to  permit  the  passage  of 
air.  An  instrument  can  bo  passed  into  it  through  the  nose  for  the  pur- 
l^ose  of  removing  obstruction  in  the  tube,  or  of  conveying  air  into  the 
tympanum. 

The  2}osterior  nares  are  the  ai^ertuYes  of  communication  between  the 
two  sides  of  the  nose  cavity  and  the  pharynx.  Each  is  elongated  from 
above  down,  and  will  admit  readily  the  tip  of  the  finger.  In  the  dried 
skull  it  is  bounded  by  the  vomer  internally  and  the  internal  pterygoid 
plate  externally,  and  by  the  body  of  the  sphenoid  above  and  the  joalate 
bone  below;  but  in  the  fresh  state  the  bones  are  clothed  by  the  mucous 
membrane,  though  without  much  diminution  in  the  size  of  the  opening. 
Separating  the  two  is  the  sejDtum  nasi,  D. 

These  apertures  allow  the  air  to  pass  in  and  out  when  the  mouth  is 
closed.  Each  is  very  much  larger  than  the  opening  in  the  face  of  the 
same  side  of  the  nasal  cavity;  and  its  increased  size  will  be  of  use  in  com- 
municating with  the  upper  part  of  the  nose,  and  in  allowing  the  outgoing 
air  to  ascend  towards  the  roof  of  the  space,  and  warm  the  parts  that  have 
been  rendered  cooler  in  inspiration. 

"When  the  lower  jaw  is  immovably  fixed,  liquid  food  can  be  passed 
into  the  stomach  by  a  small  flexible  tube  introduced  into  the  pharynx 
through  the  nose  and  the  posterior  naris. 

In  hgemorrhage  from  the  half  of  the  nose  the  fluid  may  escape  by  the 
nostril,  or  the  posterior  naris,  or  by  both  those  openings  when  the  flow 
of  blood  is  great,  and  it  may  be  needful  to  check  the  loss  of  blood  by 
stopping  both  openings.  The  aperture  in  the  face  can  be  closed  easily; 
but  the  posterior  naris  will  have  to  be  plugged  through  the  mouth. 

The  posterior  opening  of  the  mouth,  M,  is  named  isthmus  fmicium, 
and  has  the  following  bounds: — Below  lies  the  tongue,  S;  and  above  are 
the  soft  palate,  K,  and  the  uvula.  On  each  side  is  placed  the  anterior 
arch  of  the  palate,  P,  consisting  of  a  fold  of  mucous  membrane  with  fibres 
of  the  palato-glossus  muscle:  these  folds  of  opposite  sides  constitute  the 
pillars  of  the  fauces. 

This  opening  marks  the  boundary  line  between  the  mouth  and  the 
pharynx,  and  all  voluntary  control  over  the  morsel  to  be  swallowed  ceases 
at  that  spot.     The  anterior  palatine  arches  on  the  sides  of  the  aperture 


196  ILLUSTRATIONS    OF   DISSECTIONS. 

take  part  in  the  process  of  deglutition  in  this  way: — as  soon  as  the  food 
has  been  moved  backwards  by  the  tongue  to  the  isthmus,  the  lateral 
arches  are  shortened  and  moved  inwards  by  the  contraction  of  their  con- 
tained muscular  fibres,  and  shut  off  with  the  tongue  the  cavity  of  the 
mouth. 

U2}per  aperture  of  the  larynx,  V. — This  is  a  single  opening,  and  occu- 
pies the  middle  line  just  below  the  mouth.  Wide  before  and  narrow 
behind  it  is  sloped  down  and  back;  it  extends  upwards  rather  above  the 
hyoid  bone,  and  downwards  to  the  bottom  of  the  central  notch  in  the 
front  of  the  thyroid  cartilage.  In  front  it  is  bounded  by  the  wide  ex- 
panded part  of  the  epiglottis,  T;  and  behind  by  the  tips  of  the  cornicula 
laryngis,  and  by  the  arytaBnoideus  muscle  and  the  mucous  membrane. 
Laterally  it  is  limited  by  a  fold  of  mucous  membrane  (arytaeno-epiglotti- 
dean)  which  stretches  from  the  epiglottis  to  the  arytaenoid  cartilage,  and 
contains  the  depressor  muscle  of  the  epiglottis. 

Through  this  hole  the  air  is  inspired  and  expired  in  breathing;  and 
during  the  respiratory  act  the  space  remains  open  with  the  epiglottis 
raised. 

When  deglutition  is  about  to  take  place  the  larynx  is  moved  upwards 
and  forwards  under  the  hyoid  bone  and  the  tongue,  and  the  epiglottis  is 
partly  lowered;  and  during  swallowmg  the  epiglottis  is  placed  over  the 
orifice,  so  as  to  close  it  from  the  passing  food  or  drink,  whilst  the  mus- 
cular fibres  on  the  sides  and  back  of  the  opening  contract,  and  give  in- 
creased security  against  the  entrance  of  the  aliment  into  the  windpipe. 
Even  when  the  epiglottis  is  absent  the  food  does  not  find  its  way  into 
the  air  passage,  because  the  upper  part  is  sufficiently  closed  by  the  eleva- 
tion of  the  larynx,  and  by  the  contraction  of  the  muscular  fibres  around 
the  upper  opening  and  on  each  side  of  the  passage  lower  down.  If  an 
attempt  is  made  to  take  breath  during,  or  too  soon  after  a  long  draught, 
some  of  the  fluid  is  drawn  with  the  air  under  the  partially-raised  valve, 
and  produces  violent  coughing  by  irritation  of  the  larynx. 

The  aperture  of  tJie  cesopliagus,  W,  terminates  inferiorly  the  cavity  of 
the  pharynx,  and  is  placed  opposite  the  lower  edge  of  the  cricoid  carti- 
lage: it  is  circular  in  form,  and  is  surrounded  by  the  fibres  of  the  lower 
constrictor. 


THE  .SOFT    PALATE    AND    THE    TONSIL,  197 


THE  SOFT  PALATE  AND  THE  TONSIL. 

The  soft  palate  (velum  pendulum  palati)  forms  the  loose  and  movable 
part  of  the  roof  of  the  mouth,  and  depends  between  the  nose  and  mouth 
cavities.  In  a  state  of  rest  it  hangs  like  a  curtain  behind  the  mouth; 
but  it  can  be  moved  backwards  by  muscles  to  the  wall  of  the  joharynx, 
so  as  to  act  like  a  valve  in  separating  the  upper  from  the  middle  region 
of  the  pharynx. 

It  is  attached  above  by  an  aponeurosis  to  the  back  of  the  hard  palate; 
and  it  is  constructed  chiefly  of  muscles  covered  by  mucous  membrane. 
Laterally  it  is  blended  with  the  sides  of  the  pharynx.  At  the  lower  edge 
it  is  free;  and  from  its  centre  hangs  a  rounded  elongated  part,  the  uvula, 
0;  whilst  on  each  side  two  folds,  the  arches  of  the  soft  palate,  are  con- 
tinued downwards  from  it. 

The  arclies  of  the  half  of  the  soft  idalate,  P  and  E,  begin  above,  near 
the  middle  of  the  velum,  and  descend  on  the  sides  of  the  tonsil,  Q, 
diverging  from  each  other.  The  anterior,  P,  is  continued  in  front  of 
the  tonsil  to  the  side  of  the  tongue  near  the  base;  and  the  posterior  is 
directed  behind  the  tonsil  to  the  back  of  the  pharynx.  Each  consists  of 
a  fold  of  mucous  membrane  inclosing  muscular  fibres:  in  the  anterior 
fold  is  the  palato-giossus  muscle,  and  in  the  posterior  lies  the  palato- 
pharyngeus. 

Tonsil,  Q.  This  body  is  an  aggregate  of  ten  to  twenty  follicular 
glands,  like  those  over  the  root  of  the  tongue  (Kolliker),  and  it  occu- 
pies the  interval  between  the  arches  of  the  palate.  Its  size  varies  much. 
Its  situation  is  marked  by  the  presence  of  small  holes  in  the  mucous 
membrane,  without  any  surface-iarominence;  but  when  enlarged  from 
disease  it  projects,  diminishing  thus  the  size  of  the  isthmus  of  the  fauces, 
and  forms  a  swelling  which  may  be  felt  externally  near  the  angle  of  the 
jaw. 

In  its  structure  it  resembles  the  follicular  glands.  In  the  bottom  of 
the  holes  or  depressions  on  the  surface  of  the  mucous  membrane,  are 
smaller  apertures  leading  into  recesses  or  follicles;  these  recesses  are 
lined  by  mucous  membrane,  and  are  set  round  with  closed  capsules  filled 
with  a  grayish  fluid,  and  containing  cells,  and  bodies  like  free  nuclei. 
The  capsules  do  not  appear  to  have  any  apertures. 


198  ILLUSTRATIONS    OF    DISSECTIONS. 


MUSCLES  OF  THE  SOFT  PALATE. 


The  muscles  of  the  soft  palate  act  as  elevators  and  depressors.  They 
are  four  in  number  on  each  side;  and  along  the  centre  lies  a  thin  fleshy 
slip,  which  is  connected  with  the  uvula. 


G.  Levator  palati  muscle. 
H.  Tensor  palati  muscle. 
J.  Azygos  uvulae  muscle. 


K.  Superficial    part    of   the    palato- 

pharyngeus. 
L.  Deep  part  of  the  palato-pharyn- 
geus. 


The  elevator  muscles,  two  in  number  on  each  side,  G  and  H,  descend 
from  the  base  of  the  skull,  and  enter  the  soft  palate  at  their  lower  ends. 

The  levator  2Jalati,  Gr,  arises  from  the  under  surface  of  the  apex  of 
the  temporal  bone,  and  from  the  hinder  part  of  the  cartilage  of  the  Eu- 
stachian tube;  entering  the  pharynx  above  the  upper  constrictor  (Plate 
xxiv. )  it  spreads  out  in  the  soft  jDalate,  forming  a  fleshy  layer  from  the 
attached  to  the  free  edge,  and  unites  with  its  fellow  along  the  middle 
line. 

The  muscle  contracting  carries  backwards  and  upwards  the  soft  pal- 
ate, placing  this  in  a  more  horizontal  position,  and  apijroaching  the  free 
edge  and  the  uvula  to  the  back  of  the  pharynx.  By  that  movement  the 
part  of  the  pharynx  leading  to  the  nose  is  much  diminished;  and  if  the 
upper  constrictor  muscle  contracts  at  the  same  time  the  passage  may  be 
closed. 

The  tensor  vel  circumflexus  palati,  H,  has  a  thin  but  wide  origin 
from  the  skull,  and  from  the  fore  part,  of  the  cartilage  of  the  Eustachian 
tube — the  cranial  attachment  reaching  from  the  navicular  fossa  at  the 
root  of  the  internal  pterygoid  plate  to  the  styloid  process.  Descending 
along  the  inner  pterygoid  plate,  the  muscle  enters  the  pharynx  between 
two  points  of  attachment  of  the  buccinator  muscle  (Plate  xxiv.)  and 
becoming  tendinous,  turns  round  the  hamular  process  to  be  inserted 
partly  into  the  os  palati  and  partly  into  the  aj)oneurosis  of  the  palate 
beneath  the  muscles  L  and  Gr.  A  small  bursa  exists  where  the  tendon 
plays  round  the  curved  process  of  bone. 

As  this  muscle  is  attached  to  the  immovable  hard  palate  its  action 
must  be  more  limited  than  that  of  the  levator;  it  may  assist  the  special 


MUSCLES    OF    THE    SOFT    PALATE.  199 

elevator  in  bringing  the  side  of  the  soft  palate  into  a  more  horizontal 
position^  and  it  will  then  fix  and  render  tense  the  same  part  of  the 
palate. 

The  two  muscles  above  described  are  connected  with  the  cartilaginous 
part  of  the  Eustachian  tube,  and  may  act  on  it.  Taking  their  fixed  point 
below,  they  are  enabled  to  open  that  tube  which  is  ordinarily  closed,  and 
so  to  i)ermlt  air  to  enter  the  cavity  of  the  tympanum.  During  swallow- 
ing, and  during  forced  expiration  with  the  mouth  and  nose  apertures 
closed,  they  act  in  the  manner  indicated;  but  some  persons  have  the 
power  of  opening  at  will  the  Eustachian  tube,  and  driving  air  in  expira- 
tion into  the  tympanic  cavity,  without  the  nostrils  being  stopped. 

Azygos  uviilm,  J. — This  slender  muscle  shortens  the  uvula  and  the 
middle  j^art  of  the  soft  palate,  and  assists  therefore  the  elevators.  It 
consists  of  two  slips  of  pale  muscular  fibres  (only  the  right  is  seen),  which 
arise  above  from  the  palate  spine  and  the  aponeurosis  of  the  soft  palate, 
and  are  inserted  below  into  the  submucous  tissue  of  the  uvula. 

The  dejrressors  of  the  soft  jialate,  two  in  number  on  each  side,  are 
directed  downwards  in  the  folds  of  the  arches  of  the  palate  to  the  tongue 
and  the  thyroid  cartilage. 

The  palato-glossus  (constrictor  isthmi  faucium)  lies  in  the  anterior 
pillar,  P.  It  is  a  thin  narrow  slip,  which  begins  on  the  front  of  the  soft 
i^alatc,  where  it  joins  its  fellow  in  the  middle  line;  and  ends  on  the  side 
and  dorsum  of  the  tongue,  as  is  shown  in  Plate  xxvii. 

If  the  lower  end  is  fixed  it  can  draw  down  the  soft  palate,  stretching 
the  same,  so  as  to  diminish  the  space  between  the  tongue  and  the  palate; 
and  if  both  ends  are  fixed  the  muscle  will  be  moved  inwards  towards  its 
fellow,  narrowing  the  isthmus  of  the  fauces,  as  when  a  morsel  of  food  is 
about  to  be  swallowed. 

The  palato-pharyngeus  is  larger  than-  the  preceding  and  consists  of 
two  layers  in  the  palate,  which  are  separated  by  the  levator  palati  and 
azygos  uvulas  muscles. 

The  superficial  thin  layer,  K,  is  close  beneath  the  mucous  membrane, 
and  joins  at  the  middle  line  the  muscle  of  the  other  side.  The  deeper 
and  stronger  layer,  L,  unites  with  its  fellow  internally,  whilst  some  of  the 
upper  fibres  are  fixed  to  the  aponeurosis  of  the  palate.  Both  layers  meet 
at  the  outer  border  of  the  palate,  and  descend  behind  the  tonsil  in  the 
fold,  R,  to  be  inserted  mostly  in  the  back  of  the  thyroid  cartilage,  but  a 
part  blends  in  the  pharynx  with  the  upper  constrictor. 


200  ILLUSTRATIONS    OF    DISSECTIONS. 

Acting  from  below  the  muscle  will  bring  down  the  arch,  R,  and  will 
approach  the  same  to  the  uvula;  it  will  also  draw  down  and  back  the 
soft  palate  towards  the  pharynx. 

The  soft  palate  from  its  position  and  its  power  of  moving  plays  an 
important  part  in  breathing,  m  the  use  of  the  blow-pipe,  in  swallowing, 
and  in  vomiting. 

In  breathmg  with*  the  mouth  open  the  air  may  pass  through  both 
mouth  and  nose,  or  only  through  the  noso,  according  to  the  position  of 
the  mo\able  palate.  "When  the  air  obtains  ingress  and  egress  through 
both  cavities  at  the  same  time  the  velum  hangs  vertically,  as  in  the 
Drawing,  and  leaves  a  space  between  it  and  the  tongue.  When  the  air 
.is  transmitted  only  through  the  nose,  the  palate  is  applied  to  the  back  of 
.the  tongue,  and  shuts  off  the  channel  of  the  mouth. 

During  the  use  of  a  blow-pipe  the  mouth  is  first  filled  with  air,  and 
:the  soft  palate  is  then  applied  to  the  back  of  the  tongue  to  close  the 
:mouth  behind,  whilst  the  cheek-muscles  force  out  from  the  oral  space 
'through  the  lips  a  continuous  current  of  air.  At  intervals,  however,  the 
.palate  is  raised  temporarily  during  expiration  for  the  purpose  of  refilling 
with  air  the  cavity  of  the  mouth. 

In  deglutition  the  soft  palate  directs  the  aliment  into  its  downward 
■channel.  As  soon  as  the  morsel  to  be  swallowed  has  reached  the  back  of 
the  tongue  the  movable  palate  is  raised,  and  is  arched  over  it  so  as  to 
prevent  its  making  an  upward  direction  towards  the  nose.  The  depressor 
;muscles  contracting  at  the  same  time  keep  the  flap  fixed,  and  prevent  its 
retroversion;  and  as  the  palato-glossus  muscle  moves  inwards  behind  the 
•morsel,  barring  with  the  tongue  its  return  to  the  mouth,  whilst  the 
palato-pharyngeus  forms  with  the  uvula  an  inclined  plane  above  it,  the 
iood  is  conveyed  into  the  pharynx. 

In  vomiting  the  aliment  takes  a  retrograde  course  from  the  stomach 
through  the  mouth;  and  the  movable  palate  is  used  as  a  valve  to  shut  off 
the  upper  region  of  the  pharynx  and  the  nose.  The  position  of  the  velum 
during  this  act  is  similar  to  that  occupied  by  it  in  deglutition,  viz.,  it  is 
moved  somewhat  horizontally  backwards  towards  the  wall  of  the  j^harynx, 
and  the  palato-pharyngei  with  the  contracted  uvula  between  them  form 
behind  an  inclined  plane.  The  soft  palate  is  not  capable,  however,  of 
blocking  up  entirely  the  tube  of  the  pharynx,  for  some  of  the  ejected 
matter  is  forced  by  the  side  of  it  into  the  nose  cavity. 

The  ihfluence  of  the  soft  palate  on  the  voice  seems  to  be  small,  though 


PLATE  XX\/li 


FIG. 


F!G. 


^-d 


FIG 


^^^ 


H.nciickfi.l.iili  NJ 


HYOID    BONE    AND   THE    CARTILAGES    OF   THE    LARYNX.  201 

this  flap  forms  part  of  the  winding  passage  through  which  the  sound  is 
transmitted  after  its  production  by  the  vocal  cords  in  the  larynx.  In  the 
high  notes  in  singing  the  palatine  arches  and  the  uvula  are  contracted, 
but  touching  them  does  not  produce  alteration  of  the  note:  this  tense 
state  has  been  thought  to  increase  the  resonance  of  the  voice. 


VESSELS  AND  NERVES. 

The  vessels  and  nerves  appearing  in  this  dissection  have  been  noticed 
in  the  description  of  the  preceding  Plates. 


a.  Ending  of  the  external  carotid 

arteiy. 
h.  Temporal  artery. 

c.  Internal  maxillary  artery. 

d.  Internal  carotid  artery. 


e.  Inferior  laryngeal  branch. 


1.  Gustatory  nerve. 

2.  Recurrent  laryngeal  nei^e. 


DESCRIPTION  OF   PLATE  XXVII. 


Figures  ii.  and  iii.  show  the  cartilages  and  ligaments  of  the  larynx, 
with  the  vocal  apparatus;  and  in  Figure  i.  the  muscles,  vessels,  and 
nerves  are  displayed. 

In  the  preparation  made  for  Figure  ii.,  the  muscles  were  removed, 
and  the  right  half  of  the  thyroid  cartilage  was  cut  off,  except  the  fore 
part  and  the  lower  cornu;  and  then  the  muscles  and  the  mucous  mem- 
brane beneath  the  cartilage  were  taken  away  to  lay  bare  the  vocal  cord, 
and  the  arytenoid  cartilage  of  the  same  side. 

Figure  iii.  exhibits  the  interior  of  the  air  passage  in  a  larynx  and 
windpipe  slit  down  behind. 

HYOID  BONE  AND  THE  CARTILAGES  OF  THE  LARYNX. 

The  cartilages  of  the  larynx  can  be  studied  with  the  aid  of  Figures  ii. 
and  iii. ;  and  like  parts  in  both  Drawings  are  marked  by  the  same  letters 
of  reference. 


202 


ILLUSTRATIONS    OF    DISSECTIONS. 


A.  Great  cornu  of  the  hyoid  bone. 

B.  Body  of  the  os  hyoides. 

C.  Small  cornu  of  the  kyoid. 

D.  Thyroid  cartilage. 

E.  Upper  cornu  of  the  thyroid. 

F.  Lower  cornu  of  the  thyroid. 

G.  Cricoid  cartilage. 

H.  Arytsenoid  cartilage. 

I.  Cartilage  of  Santorini. 

J.  Crico-arytaenoideus  posticus  mus- 

.;le. 
K.  Cuneiform  cartilage. 

L.  Epiglottis. 


M.  Thyro-hyoid  ligament. 

N.  Crico-thyroid  ligament. 

O.  True  chorda  vocahs. 

P.  False  chorda  vocalis. 

Q.  Ventricle  of  the  larynx. 

R.  Rima  glottidis. 

S.  Sacculus  laryngis. 

T.  Thyro-hyoid  membrane. 

U.  Arytasno-epiglottid.  fold. 

V.  Axytgenoideus  posticus  muscl 
W.  Interior  of  the  trachea. 
X.  Muscular  part  of  the  trachea. 
Y.  Rings  of  the  trachea. 


The  hyoid  or  U-shaped  hone  is  placed  between  the  tongue  and  the 
larynx,  to  both  of  which  it  gives  attachment.  It  consists  of  a  central 
part  or  body,  and  of  two  lateral  pieces  on  each  side — the  cornua. 

The  body,  B,  is  the  deej)est  part  of  the  bone:  it  is  convex  and  uneven 
in  front,  and  concave  and  smooth  behind.  Elevator  and  depressor 
muscles  are  fixed  into  the  fore  part;  and  by  its  upper  edge  it  gives 
attachment  to  the  fibrous  membrane  of  the  tongue,  and  that  of  the 
larynx. 

The  cornua  articulate  with  each  side  of  the  body.  The  large  one.  A, 
projects  backwards  behind  the  tongue,  and  is  joined  by  muscles  of  the 
phaiynx,  larynx,  and  tongue.  The  small  cornu,  C,  is  a  short  rounded 
process,  to  which  the  stylo-hyoid  ligament  (X,  Fig.  i.)  is  connected. 

Cartilages,  of  the  larynx.  There  are  several  pieces  of  cartilage  in  the 
larynx  as  in  the  trachea;  but  they  differ  in  their  nature.  One  set  resem- 
bles the  permanent  cartilages  of  the  ribs,  and  like  them  is  prone  to  ossify; 
the  other  set,  consisting  of  small  joieces,  is  constructed  of  yellow  cartilage, 
as  in  the  eyelid,  and  is  not  transmuted  into  bone. 

The  large  and  firm  cartilages,  which  are  more  or  less  ossified  in  the 
adult,  are  more  immediately  connected  with  the  vocal  cords:  they  are 
four  in  number,  viz.,  the  thyroid,  cricoid,  and  two  arytaenoid. 

The  thyroid  cartilage,  D,  is  the  largest  and  highest,  and  is  named 
from  protecting  the  rest  like  a  shield.  It  is  formed  of  two  similar  halves, 
which  are  widely  separated  behind,  and  are  united  in  front  at  an  acute 
angle,  so  as  to  be  prominent  beneath  the  skin  (pomuni  Adami). 

Each  half  ends  posteriorly  in  a  rounded  thickened  border,  which  is 
prolonged  above  and  below  into  a  point — the  cornua:  of  these,  the  upper 


THE   .CARTILAGES    OF    THE    LARYNX.  203 

cornii,  E,  is  tlie  longest,  and  tlie  lower  one,  F,  articulutcs  Avith  the  cri- 
coid cartilage. 

Externally  muscles  of  the  pliarynx  and  larynx  are  fixed  into  the  thy- 
roid; and  internally  it  receives  the  insertion  of  the  vocal  cords  and  of  the 
muscles  acting  on  those  cords. 

The  cricoid  cartilage,  G,  forms  a  ring  around  the  air  passage,  and  is 
much  deeper  behind  than  before,  like  a  signet  ring.  On  its  upper  bor- 
der at  the  back  are  seated  the  two  aryt^enoid  cartilages;  and  outside  and 
below  these  the  lower  cornua  of  the  thyroid  cartilage  rest  on  it.  Inter- 
nally it  is  smooth  and  is  lined  by  mucous  membrane;  and  externally 
muscles  are  attached  to  it. 

The  part  of  the  larynx  inclosed  by  this  cartilage  is  quite  inextensible ; 
and  by  means  of  the  great  depth  of  the  cricoid  behind,  the  arytaenoid 
cartilages  are  raised  to  the  height  needful  for  the  attachment  of  the  vocal 
cords  to  them. 

The  arytmnoid  cartilages  are  something  like  a  pitcher  in  shape,  and 
are  placed  at  the  back  of  the  larynx.  Each  is  pyramidal  in  form,  with 
the  base  resting  on  the  upper  border  of  the  cricoid  cartilage,  and  the  apex 
blending  with  the  cartilage  of  Santorini,  I.  Narrow  and  smooth  inter- 
nally or  toAvards  its  fellow,  it  is  widened  and  rough  externally  where 
muscles  are  inserted  into  it.  Fig.  ii.,  H.  Its  posterior  part  is  hollowed, 
and  lodges  the  arytaenoid  muscle;  and  from  its  fore  part  projects  a  spur 
into  which  the  vocal  cord,  0,  is  fixed. 

This  is  the  most  movable  of  the  laryngeal  cartilages;  and  as  the  vocal 
cord  and  most  of  the  muscles  altering  the  condition  of  that  cord  are  con- 
nected with  it,  the  production  and  modification  of  the  voice  are  influenced 
by  its  position. 

The  remaining  small  cartilages  do  not  take  part  in  the  production  of 
the  voice,  though  they  may  assist  in  modifying  the  same  after  it  is  formed, 
and  they  are  therefore  of  secondary  import.  Five  in  number,  the  chief 
of  them  acts  as  a  valve  to  the  upper  opening  of  the  larynx,  and  is  called 
epiglottis:  the  others  are  two  pairs,  one  being  named  cartilages  of  San- 
torini, and  the  second,  cartilages  of  Wrisberg. 

The  cartilages  of  Santorini,  I  (cornicula  laryngis),  are  placed  on  the 
tops  of  the  arytaenoid  cartilages.  Wide  below  they  gradually  taper  above, 
the  points  bending  towards  each  other. 

Thev  bound  posteriorly  the  upper  laryngeal  opening;  and,  enveloped 


204  ILLCSTEATIONS    OF    DISSECTIONS. 

by  the  mucous  membrane,  serve  for  the  attachment  of  the  folds,  U, 
bounding  laterally  that  opening. 

The  cartilages  of  Wrislerg,  K,  Fig.  ii.  (cuneiform  cartilages),  are 
placed  in  front  of  the  cornicula,  one  in  each  arytseno-epiglottid.  fold  U. 
Each  resembles  a  gi-ain  of  rice  in  shape  and  size.  The  use  of  these  is  not 
known:  they  are  not  connected  to  the  otlier  cartilages  by  ligamentous 
bands. 

The  epiglottis,  L,  stands  in  front  of  the  opening  into  the  larynx 
(Plate  xxvi.).  Shaped  like  a  leaf,  with  the  wide  part  up  and  the  pedicle 
down,  it  is  attached  by  fibrous  tissue  to  the  thyroid  cartilage.  Its  hinder 
or  laryngeal  surface  has  a  smooth  covering  of  mucous  membrane  with 
apertures  for  glands  in  its  substance;  and  tlie  fore  part  is  connected  to 
the  tongue  by  a  central  and  two  lateral  folds  of  mucous  membx'ane. 
From  each  side  is  continued  the  arytasno-epiglottid.  fold. 

This  valve  is  employed  in  closing  the  laryngeal  opening  during  deglu- 
tition (p.  19G).  And  when  placed  over  the  opening  during  the  produc- 
tion of  vocal  sounds  it  causes  the  pitch  of  the  note  to  be  lowered.  • 

AETICULATIOXS   OF  THE  CARTILAGES. 

The  larger  laryngeal  cartilages  are  articulated  together  by  means  of 
joints  where  the  extent  of  movement  is  great;  and  the  larynx  is  further 
united  to  the  hyoid  .bone  above  and  the  trachea  below  by  fibrous  mem- 
brane. 

The  cricoid  and  thyroid  cartilages  are  articulated  at  two  points,  viz., 
laterally  and  in  front. 

Laterally  there  is  a  joint  on  each  side  between  the  lower  comu,  F, 
of  the  thyroid  and  the  side  of  the  cricoid,  in  which  an  inclosing  capsule 
and  a  lining  synovial  membrane  are  present.  By  means  of  this  joint  the 
front  of  the  thyroid  cartilage  can  be  approximated  to  or  removed  from 
the  cricoid.  When  the  thyroid  is  depressed  the  vocal  cords  are  tight- 
ened, and  when  it  is  raised  or  carried  backwards  they  are  relaxed. 

Anteriorly  a  strong  elastic  membrane,  crico-thyroid,  N,  closes  the 
interval  between  the  two.  By  its  lower  edge  it  is  inserted  into  the 
upper  border  of  the  cricoid  as  far  back  as  the  arytainoid  cartilage.  Above 
it  joins  the  lower  border  of  the  thyroid  for  a  short  distance,  also  the 
spur  on  the  front  of  the  arytsenoid;  and  between  those  fixed  points  it 
forms  a  free  edge,   0,  the  vocal  cord.      This  free  upper  edge  can  be 


AETICULATIONS   OF   THE   CARTILAGES.  205 

tigliteiied  or  rendered  lax  by  the  thyroid  cartilage  being  depressed  or 
raised. 

Between  the  arytenoid  and  cricoid  cartilages  there  is  a  very  mov- 
able joint  with  a  fibrous  capsule  surrounding  the  articular  surfaces,  and 
a  synovial  membrane  lubricating  them.  In  this  joint  the  arytcenoid  car- 
tilage can  slide  on  the  cricoid  forwards  and  backwards,  and  inwards  and 
outwards;  and  further,  when  the  arytenoid  is  controlled  by  the  muscles 
tending  to  draw  it  in  opposite  directions,  it  can  be  rotated  round  a  ver- 
tical axis  so  as  to  move  the  anterior  spur  outAvards  and  inwards. 

The  condition  of  the  vocal  cord,  0,  is  altered  by  the  movements  of 
the  cartilage.  Thus  it  is  relaxed  when  the  arytsenoid  is  carried  forwards, 
and  is  tightened  when  the  same  is  moved  backwards;  and  the  distance  of 
the  cords  from  one  another  will  be  increased  and  diminished  as  the  two 
cartilages  are  moved  from  and  towards  each  other.  In  rotation  out  the 
cords  are  separated  and  made  tense,  and  in  rotation  in  they  are 
approached,  but  without  being  relaxed. 

The  smaller  or  accessory  cartilages  are  articulated  by  ligamentous 
bands,  but  have  not  movable  joints  as  in  the  larger  cartilages. 

The  cartilages  of  Santorini  are  united  to  the  top  of  the  arytsenoid 
by  surrounding  fibrous  tissue:  but  at  times  there  is  some  indication  of  a 
joint  between  the  base  of  the  one  and  the  apex  of  the  other. 

The  epiglottis  is  fixed  below  by  a  band  (thyro-epiglottid)  to  the  thy- 
roid cartilage,  close  below  the  notch  in  the  upper  border;  and  in  front  it 
is  united  to  the  back  of  the  hyoid  bone  by  fibrous  tissue — the  hyo-epi- 
glottid  ligament. 

The  larynx  joins  the  trachea  below  by  a  membrane  similar  to  that 
connecting  the  rings  of  this  tube;  and  it  is  attached  to  the  hyoid  bone 
above  by  the  following  ligament. 

The  thyro-liyoid  membrane,  T,  is  thin  for  the  most  part,  but  it  forms 
rounded  thicker  cords  behind — the  thyro-hyoid  ligaments,  M.  It  is  in- 
serted below  into  the  upper  edge  of  the  thyroid  cartilage;  but  it  is  contin- 
ued onwards  to  the  upper  edge  of  the  os  hyoides,  muscles  shutting  it  out 
from  the  lower  edge  of  that  bone:  a  synovial  membrane  intervenes  between 
the  two. 


206  ILLUSTKATIONS    OF   DISSECTIONS. 


INTERIOR  OF  THE  LARYNX  AND  THE  VOCAL  APPARATUS. 

The  larynx  or  the  dilate!  upj)er  part  of  the  windpij^e  is  wider  above 
than  below;  and  the  space  inclosed  within  the  cartilages  varies  in  form 
and  size  at  different  points.  As  a  whole  the  larynx  measures  about  one 
inch  and  a  half  from  above  down,  one  inch  and.  a  quarter  across  at  the  top, 
and  about  an  inch  across  at  the  lower  part. 

The  laryngeal  cavity  (Fig.  iii.)  communicates  above  with  the  pharynx 
by  the  epiglottid.  aperture,  and.  below  with  the  trachea.  By  means  of 
muscles  and  the  mucous  membrane  the  space  inside  the  thyroid  cartilage 
decreases  in  width  from  the  epiglottis  to  the  level  of  the  vocal  cords,  0, 
where  only  a  narrow  fissure — the  glottis  remains;  but  just  above  the  vocal 
cord  is  a  dilatation  on  each  side,  Q,  which  is  named  the  ventricle  of  the 
larynx.  Beyond  the  vocal  cords  the  space  enlarges  to  the  size  of  the  cri- 
coid cartilage,  and  becomes  circular.  Its  shaj)e  is  something  like  an  hour- 
glass, the  glottis,  E,  corresponding  with  the  narrowest  part  of  that  instru- 
ment. 

Vocal  apparatus.  Under  this  general  term  may  be  included  the  vocal 
cords,  with  the  chink  or  interval  between  them;  and  the  ventricle  of  the 
larynx  and  its  pouch. 

The  vocal  cords  are  two  whitish  bands  on  each  side,  which  shine 
through  the  mucous  membrane,  and  lie  above  and  below  the  ventricular 
space,  Q.  Both  are  stretched  between  the  thyroid  cartilage  in  front,  and 
the  arytasnoid  behind. 

The  upper  land,  P,  or  the  false  vocal  cord,  forms  a  curve  with  the 
convexity  upwards.  In  front  it  is  fixed  to  the  thyroid  cartilage  slightly 
above  the  middle;  and  behind  to  the  outer  part  of  the  arytsenoid.  It 
consists  of  a  bundle  of  white  fibrous  tissue,  which  is  covered  by  the 
mucous  membrane. 

The  use  of  this  band  is  unknown.  The  voice  is  not  produced  by  it, 
for  it  is  removed  so  far  from  the  centre  of  the  laryngeal  space  as  to  be 
out  of  reach  of  the  direct  current  of  air. 

The  lower  or  true  cord,  0,  Fig.  ii.,  is  stronger  than  the  other,  and  is 
horizontal  in  direction.  It  is  inserted  in  front  into  the  thyroid  cartilage 
about  the  centre  of  its  depth,  and  behind  into  the  anterior  spur  at  the 
base  of  the  arytaenoid  cartilage.     In  the  male  it  measures  rather  more 


INTERIOR    OF    THE    LARYNX.  207 

than  half  an  inch,  and  in  the  female  rather  less.  This  band  forms  the 
upper  free  edge  of  the  crico-thyroid  ligament  (Fig.  ii.,  N),  and  consists 
of  a  bundle  of  fine  elastic  tissue  covered  by  thin  mucous  membrane. 

It  has  two  free  surfaces,  one  internal  whicli  looks  to  its  fellow,  and  one 
above  where  it  bounds  the  ventricle;  and  the  free  edge  between  those 
two  surfaces  is  the  part  that  is  made  to  vibrate  by  the  outgoing  current 
of  air. 

Sound  or  voice  is  produced  by  the  expired  air  throwing  into  vibration 
the  free  edges  of  the  lower  two  vocal  cords.  In  breathing  the  vibrating 
edges  are  at  a  distance  from  each  other,  and  divergent  behind,  and  the 
air  passes  by  them  without  sound.  In  order  that  voice  should  be  pro- 
duced those  edges  require  to  be  approximated  and  put  jjarallel  to  each 
other  by  muscles,  and  so  to  be  brought  into  the  state  called  the  vocalizing 
position. 

The  pitch  of  the  voice  varies  with  the  degree  of  tightness  or  laxness 
of  the  vocal  cords.  If  the  cords  are  loose  a  deep  sound  ensues,  but  if 
they  are  tight,  a  high  tone  is  formed.  Alterations  in  the  degree  of  ten- 
sion depend  upon  the  action  of  controlling  muscles. 

The  glottis  (rima  glottidis),  R,  is  the  narrow  interval  or  chink  between 
the  true  vocal  cords.  Its  extent  is  greater  than  that  of  the  cords,  for  it 
reaches  across  the  larynx;  and  it  is  bounded  on  each  side  by  the  vocal 
cord  and  the  arytsenoid  cartilage.  It  measures  from  before  back  nearly 
an  inch,  and  across  at  the  base  when  dilated  about  a  third  of  an  inch: 
both  measurements  refer  to  the  larynx  of  the  male.  In  the  female  the 
size  is  less  by  two  or  three  lines.  During  inspiration  the  space  is  larger 
than  in  expiration. 

Its  form  changes  with  the  dilatation.  In  a  state  of  rest  the  interval 
resembles  a  spear-head  with  the  shaft  placed  backwards;  when  dilated  it 
is  triangular  in  form,  the  base  of  the  interval  being  behind. 

The  ventricle  of  the  larynx,  Q,  is  the  hollow  between  the  false  and 
true  vocal  cords  of  the  same  side;  and  it  extends  from  the  thyroid  to  the 
arytgenoid  cartilage.  The  bottom  of  the  hollow  is  wider  than  the  open- 
ing into  the  larynx;  and  at  its  upper  and  anterior  part  it  communicates 
with  the  sacculus  laryngis,  S.  Into  this  holloAV  the  mucous  membrane 
sinks,  and  after  lining  the  space,  enters  the  laryngeal  pouch. 

This  space  by  its  position  isolates  the  true  vocal  cord  from  the  wall  of 
the  larynx,  and  permits  the  free  vibration  of  that  band. 

The  laryngeal  pouch  (sacculus  laryngis),  S,  is  a  small  conical  bag  of 


208  ILLTJSTEATIONS    OF   DISSECTIONS. 

the  mucous  membrane,  which  projects  upwards  from  the  ventricle  of  the 
larynx,  and  when  distended  reaches  as  high  as  the  upper  border  of  the 
thyroid  cartilage.  Fig.  ii.  gives  an  inner  view  of  its  position  on  the  side 
of  the  epiglottis;  and  in  Fig.  i.  it  is  seen  from  the  outside  as  it  rises  above 
the  thyro-arytaenoid  muscle,  P. 

Closed  and  dilated  above,  the  pouch  is  narrow  below;  and  it  opens  into 
the  ventricle  by  a  small  hole,  which  is  diminished  somewhat  by  a  pro- 
jection of  the  mucous  membrane.  Over  the  outer  surface  arc  scattered 
numerous  mucous  glands  (sixty  or  seventy  in  number)  which  open  by 
small  ducts  on  the  inner  surface,  and  j^our  their  secretion  over  the  con- 
tiguous parts,  viz.,  the  ventricle  and  the  vocal  cords. 

The  mticous  lining  of  the  larynx  forms  a  fold,  U  (arytaeno-epiglottid), 
on  each  side  of  the  upper  orifice,  and  extends  through  the  cavity  to  the 
trachea.  Furnishing  a  very  thin  covering  without  glands  to  the  vocal 
cords,  it  sinks  into  the  ventricle  between  them,  and  gives  rise  to  the  sac- 
culus.  As  low  as  the  vocal  cords  it  is  loosely  united  to  the  subjacent 
joarts  by  areolar  tissue,  but  it  is  joined  closely  to  those  bands  without  the 
intervention  of  any  submucous  stratum.  In  consequence  of  the  closeness 
of  its  attachment  to  the  cords  the  swelling  from  fluid  effused  into  the 
areolar  tissue  in  oedema  of  the  glottis  does  not  extend  below  that  point; 
and  thus,  though  the  upper  orifice  of  the  larynx  may  be  closed  by  the 
swelling,  air  can  be  admitted  to  the  lungs  by  an  artifical  aperture  through 
the  crico-thyroid  membrane,  N,  as  in  the  operation  of  laryngotomy,  be- 
cause this  opening  will  be  situate  below  the  swollen  parts. 

FiGUEE  I. — For  this  Drawing  the  dissection  was  prepared  by  removing 
the  greater  part  of  the  right  half  of  the  thyroid  cartilage,  and  then  taking 
the  areolar  tissue  from  the  subjacent  muscles,  vessels,  and  nerves.  Some 
nerves  which  enter  the  mucous  membrane  behind  the  larynx  from  both 
laryngeal  trunks  could  not  be  preserved. 

On  the  right  side  of  the  tongue  the  extrinsic  muscles  have  been  defined 
as  they  enter  it. 

In  this,  as  in  the  other  Figures,  the  hyoid  bone,  the  cartilages  of  the 
larynx  with  some  ligaments,  and  the  trachea  and  the  thyroid  body  are  de- 
picted. 


A.  Os  hyoides. 

B.  Thyroid  cartilage. 

C.  Cricoid  cartilage. 

D.  Trachea. 


E.  The  tongue. 

F.  Palato-glossus  muscle. 

G.  Stylo-glossus. 

H.  Pharyngeo-glossus. 


MUSCLES    OF    THE    LARYNX. 


209 


I.    Coniicula  laryngis. 

J.    Crico-thyroid  membrane. 

K.  Hyo-glossus  muscle. 

L.  The  epiglottis. 

M.  Genio-hyo-glossus. 

N.  Thyro-hyoid  membrane. 


S.    Sacculus  laryngis. 

T.    Thyroid  body. 

U.  Pyramid  of  the  thyroid  body. 

W.  Levator  glandulae  thyreoideae. 

X.  Stylo-hyoid  ligament,  ossified. 

Z.  Upper  part  of  the  oesophagus. 


MUSCLES  OF  THE  LARYNX. 

Some  of  the  intrinsic  laryngeal  muscles  act  more  immediately  on  the 
arytgenoid  cartilages,  approximating  them  to,  or  removing  them  from 
each  other,  and  control  the  width  of  the  glottis.  Others  make  tense  or 
lax  the  vocal  cords,  and  so  govern  the  pitch  of  the  voice.  One  pair  of 
muscles  depresses  the  epiglottis. 


O.  Depressor  of  the  epiglottis. 

P.  Thyro-arytaenoideus. 

Q.  Crico-arytaenoideus  lateralis. 


R.  Crico-arytsenoideus  posticus. 

V.  Arytaenoideus. 

Y.  Crico-thyroideus,  cut. 


Muscles  govering  the  size  of  the  glottis. — The  interval  between  the 
vocal  cords  can  be  widened  or  narrowed  by  the  three  following  muscles. 

The  crico-arytmnoideus posticus,  R  (J,  Fig.  iii.),  arises  from  the  right 
lateral  depression  on  the  back  of  the  cricoid  cartilage,  and  is  inserted 
above  into  the  base  of  the  arytenoid  cartilage  at  the  outer  side. 

When  this  muscle  acts  the  arytsenoid  cartilage  will  be  rotated  around 
its  vertical  axis,  and  the  anterior  spar  will  be  moved  outwards  away  from 
the  middle  line.  By  this  movement  the  glottis  is  widened  at  the  base, 
and  the  upper  aperture  of  the  larynx  is  also  made  larger. 

The  crico-arytmnoideus  lateralis,  Q,  arises  from  the  upper  edge  of  the 
cricoid  cartilage,  at  the  lateral  aspect;  and  taking  a  backward  direction 
it  is  inserted  with  the  preceding  into  the  external  prominence  at  the  base 
of  the  arytsenoid  cartilage,  and  into  the  contiguous  part  of  the  outer  sur- 
face. 

As  the  preceding  muscle  moves  outwards  the  external  projection  of 
the  cartilage,  the  lateral  crico-arytaenoideus  is  put  on  the  stretch;  but  as 
soon  as  the  posterior  muscle  ceases  to  contract,  the  lateral  one  will  restore 
the  displaced  cartilage  to  its  usual  position.  This  muscle,  acting  by  it- 
self, will  turn  inwards  the  anterior  spur,  and  diminish  the  width  of  the 

glottis. 

14 


210  ILLUSTRATIONS    OF    DISSECTIONS. 

The  arytcBnoideus,  V,  the  only  single  muscle  of  the  larynx,  cioses  the 
interval  between  the  arytasnoid  cartilages.  It  consists  mostly  of  transverse 
fibres,  which  are  attached  to  the  hollowed  posterior  surfaces  of  the  carti- 
lages; but  it  possesses  also  two  superficial  bands,  which  are  directed froni 
the  base  of  one  cartilage  to  the  apex  of  the  other.  These  oblique  slips 
cross  each  other  at  the  middle,  and  join  in  front  the  thyro-arytaenoideus 
and  the  depressor  epiglottidis. 

The  fibres  of  the  muscle  contracting  will  draw  the  arytsenoid  cartilages 
towards  each  other,  and  diminish  the  width  of  the  glottis.  And,  as  this 
movement  approximates  the  vocal  cords,  the  muscle  is  one  of  the  two  em- 
ployed in  placing  the  cords  in  the  vocalizing  position.  The  muscle 
diminishes  behind  the  width  of  the  upper  laryngeal  orifice. 

Muscles  governing  the  intcli  of  the  voice. — The  muscles  making  tight 
or  loose  the  vocal  cords,  and  rendering  the  voice  either  high  or  deep  in 
tone,  are  the  two  subjoined. 

The  thyro-arytcenoideits  muscle,  P,  lies  outside  the  vocal  cord  of  the 
same  side,  to  which  it  is  closely  united.  Anteriorly  it  arises  from  the 
lower  half  (in  depth)  of  the  thyroid  cartilage,  and  from  the  contiguous 
crico-thyroid membrane;  audit  is  inserted  behind  into  the  base  and  outer 
surface  of  the  arytenoid  cartilage.  Its  inner  and  lower  fibres  are  trans- 
verse, but  the  outer  ascend  and  join  the  depressor  of  the  epiglottis,  0. 

Through  the  action  of  this  muscle  the  arytaenoid  will  be  drawn  for- 
wards towards  the  thyroid  cartilage,  and  the  vocal  cord  of  the  same  side 
will  be  relaxed,  as  when  deep  or  grave  sounds  are  produced.  The  muscle 
is  supposed  (Willis)  to  have  the  power  of  placing  the  inner  vibrating  edge 
of  the  vocal  cord  parallel  to  its  fellow. 

The  crico-thyroid  muscle,  Y,  can  be  seen  entire  in  Plate  xxiv.  Placed 
on  the  front  of  the  larynx,  it  arises  from  the  side  and  fore  part  of  the  cri- 
coid cartilage;  and  it  is  inserted  into  the  inferior  cornu,  and  the  lower 
border  of  the  thyroid  cartilage  nearly  to  the  middle  line. 

Supposing  the  attachment  to  the  cricoid  cartilage  to  be  the  fixed  point, 
the  muscles  of  opposite  sides  will  bring  down  the  thyroid  cartilage  in  front. 
By  this  movement  the  interval  between  the  arytaenoid  and  thyroid  carti- 
lages is  increased,  and  consequently  the  vocal  cords  are  tightened,  and  put 
into  the  state  necessary  for  the  production  of  a  high  note.  If  the  thyroid 
is  supposed  the  fixed  point,  the  front  of  the  cricoid  will  be  raised,  whilst 
the  back  of  the  same  with  the  arytaenoid  cartilages  will  be  lowered,  and 
the  vocal  cords  will  be  likewise  stretched. 


NERVES    OF    THE    LARYNX. 


211 


The  depressor  cf  the  epiglottis,  0  (thyro-arytgeno-epiglottideus),  is  a 
thin  and  indistinct  kyer  of  muscular  fibres,  which  is  contained  in  the 
arytfeno-epigiottid  fold,  U,  and  consists  usually  of  two  parts.  The  chief 
I)undle  of  fibres  comes  from  the  top  of  the  arytenoid  cartilage,  where  it 
is  continuous  with  the  thyro-arytsenoideus  and  arytsenoideus  muscles; 
and  the  other  slip  is  attached  to  the  thyroid  cartilage  near  the  insertion 
of  the  epiglottis.  The  fibres  of  the  muscle  ascend  on  the  side  of  the 
opening  of  the  larynx,  and  are  inserted  into  the  margin  of  the  epiglottis. 

The  lower  fibres  of  the  muscle  cross  the  top  of  the  sacculus  laryngis, 
and  are  supposed  by  Mr.  Hilton  to  compress  the  sac :  this  part  has  been 
named  by  him  arytmno-epiglottideus  i^iferior.* 

In  swallowing  the  epiglottis  may  be  lowered  by  the  action  of  the 
muscles  of  both  sides,  after  the  larynx  has  been  elevated;  and  the  laryn- 
geal orifice  can  be  diminished  by  the  shortening  and  moving  inwards  of 
the  arytaeno-epiglottid  fold.  In  the  production  of  very  deep  notes  the 
muscles  draw  down  the  epiglottis  over  the  aperture  of  the  larynx. 


NERVES  OF  THE  LARYNX. 

There  are  two  laryngeal  nerves  on  each  side,  the  superior  and  inferior. 
One  is  supplied  nearly  altogether  to  the  mucous  membrane,  and  the  other 
chiefly  to  muscles. 


1.  Upper  laryngeal  nerve. 

2.  Branches  to  the  mucous  mem- 

brane of  the  larynx. 

3.  Branch  for  the  arytsenoideus. 

4.  Branch  to  join  inferior  laryngeal. 

5.  Inferior  laryngeal    or    recurrent 

nerve. 


6.  Branch  to  join  upper  laryngeal. 

7.  Branch  to  nauscles. 

8.  Hypoglossal  nerve. 

9.  Glosso-pharyngeal  nerve. 
10.  Gustatory  nerve. 


The  upper  laryngeal  nerve,  1,  pierces  the  thyro-hyoid  membrane,  and 
divides  into  branches.  From  the  branch,  2,  offsets  are  distributed  to  the 
root  of  the  tongue,  and  to  the  mucous  membrane  of  the  larynx;  between 
the  border  of  the  epiglottis  and  the  true  vocal  cord,  one  or  two  pierce  the 
depressor  of  the  epiglottis.     The  branch  3  enters  the  arytsenoideus  mus- 


*  Description  of  the  sacculus  or  pouch  in  the  human  larynx.     By  Mr  Joim 
Hilton.    GuyV  (hospital  Reports,  vol.  2.     Lond.  1837,  p.  519. 


212  ILLUSTEATIONS    OF    DISSECTIONS. 

cle,  Y,  and  supplying  it,  passes  through  to  the  mucous  lining  of  the 
larynx.  From  the  branch,'  4,  offsets  are  furnished  to  the  pharyngeal 
mucous  membrane;  and  this  Joins  finally  the  recurrent  laryngeal  nerve. 

Before  the  nerve  enters  the  larynx  it  gives  off  high  in  the  neck  the 
external  laryngeal  branch  (Plate  xxiv.  4),  which  ends  in  the  crico-thy- 
roideus  muscle,  Y,  supplying  it  entirely. 

The  upper  laryngeal  is  the  sensory  nerve  of  the  mucous  membrane  of 
the  larynx  as  low  as  the  true  vocal  cord;  and  by  its  extreme  sensibility  it 
guards  the  upper  part  of  the  passage  against  the  entrance  of  anything 
but  the  air.  As  soon  as  a  particle  of  food  or  drink  touches  the  lining 
membrane,  the  respiratory  muscles  are  called  into  play  by  a  reflex  act, 
and  the  foreign  body  is  expelled  by  coughing.  In  the  attempt  to  breathe 
an  irrespirable  gas  the  passage  is  closed  by  the  contraction  of  the  sur- 
rounding muscles,  also  through  a  reflex  act.  When  the  nerve  is  cut 
across  in  an  animal  during  life  the  sensibility  of  the  part  is  lost,  and  food 
may  enter  the  larynx. 

To  the  crico-thyroideus  muscle,  which  it  supplies  alone,  it  gives  motor 
influence  as  w^ell  as  sensibility;  and  to  the  arytsenoideus,  to  which  with 
the  recurrent  it  furnishes  offsets,  it  imparts  only  sensibility. 

The  inferior  laryngeal  or  recurrent  nerve,  5,  ascends  over  the  side  of 
the  cricoid  cartilage,  and  ends  in  muscular  offsets  beneath  the  thyroid. 
At  first  the  nerve  supplies  branches  to  the  mucous  membrane  of  the 
pharynx,  and  the  communicating  branch,  G,  which  joins  the  upper  laryn- 
geal under  the  thyroid  cartilage.  The  continuation  of  the  nerve,  7,  then 
terminates  in  branches  for  muscles: — one  belongs  to  the  crico-arytasnoid- 
eus  posticus,  E;  a  second,  which  passes  beneath  the  preceding  muscle, 
enters  the  arytsenoideus,  Y;  and  another  gives  nerves  to  the  crico-arytse- 
noideus  lateralis,  Q,  and  the  thyro-arytsenoideus,  P.  In  short,  the  nerve 
supplies  all  the  special  laryngeal  muscles  except  the  crico-thyroideus,  Y, 
which  receives  the  external  laryngeal  branch  of  the  superior  laryngeal 
nerve.  * 

*  Anatomists  axe  silent  for  the  most  part  respecting  the  nerve  to  the  muscle 
here  called  depressor  of  the  epiglottis;  but  Mr.  Hilton  states  (Guy's  Hospital  Re- 
ports, vol.  2,  1837)  as  the  result  of  "repeated  and  careful  dissections"  that  it  is 
supplied  from  the  recurrent  nerve  by  means  of  two  filaments  which  are  prolonged 
from  the  branch  of  the  same  nerve  to  the  thyro-aryt^noideus.  Neither  in  my 
own  dissections,  nor  in  those  of  Mr.  P.  B.  Mason  and  Mr.  J.  S.  Cluff,  formerly 
Demonstrators  of  Anatomy,  could  any  separate  branch  be  traced  from  the  recur- 


VESSELS    OF    THE    LARYNX. 


213 


The  recurrent  is  the  motor  nerve  of  the  muscles  acting  on  the  vocal 
cords,  to  all  of  which,  except  to  the  crico-thyroideus,  it  gives  branches. 
But  it  must  bestow  sensibility  by  means  of  the  offsets  ramifying  in  the 
mucous  membrane. 

If  the  recurrent  nerves  are  cut  tlirough,  the  muscles  are  paralyzed; 
and  as  the  vocal  cords  cannot  be  placed  in  the  vocalizing  position,  and 
cannot  receive  the  necessary  degree  of  laxity  or  tension,  voice  will  not  be 
produced. 


VESSELS  OF  THE  LARYNX. 

Two  arteries  on  each  side,  which  are  companions  to  the  nerves,  ramify 
in  the  larynx;  they  are  named  upper  and  lower  laryngeal.  Other  small 
arteries  from  the  upper  thyroid  enter  the  larynx,  below,  by  perforating 
the  crico-thyroid  membrane. 


a.  Upper  laryngeal  artery. 

b.  Ascending  branch    (  of  the  upper 

c.  Descending  branch  1       artery. 

d.  Communicating    branch  of    the 

upper  laryngeal. 

e.  Communicating    branch    of    the 

lower  laryngeal  artery. 


/.  Muscular  branch  of  lower  laryn- 
geal. 

g.  Inferior  laryngeal  artery. 

h.  Branches  of  superior  thyroid  ar- 
tery to  the  thyroid  body. 

k.  Branches  of  inferior  thyroid  artery 
to  the  under  part  of  the  thyroid 
body. 


The  iqyper  laryngeal  artery,  a,  resembles  the  nerve  of  the  same  name 
in  its  branches,  but  it  is  not  distributed  so  exclusively  to  the  mucous 
membrane.  The  offsets,  l  and  c,  supply  the  mucous  membrane  from  the 
root  of  the  tongue  to  the  chorda  vocalis;  and  from  c,  arteries  are  furnished 
to  the  muscles,  0,  P,  and  Q,  under  the  thyroid  cartilage,  and  to  the  crico- 
thyroideus,  Y.  The  branch,  d,  anastomoses  with  the  inferior  laryngeal 
both  under  the  thyroid  cartilage,  and  in  the  mucous  membrane  of  the 
pharynx. 

The  inferior  laryngeal,  g,  gives  branches  to  the  posterior  laryngeal 
muscles,  R  ana  V,  and  to  Q  in  part;  and  it  joins  the  upper  laryngeal 
outside  the  thyro-arytsenoideus  muscle,  P.  Branches  of  it  enter  the 
mucous  membrane  of  the  pharynx,  and  communicate  again  Avith  the 
upper  laryngeal  by  the  offset,  e. 

rent  nerve  to  the  muscle.     Mr.  Cluff  made  six  special  examinations  of  the  human 
larynx,  one  of  the  larynx  of  a  donkey,  and  one  of  the  larynx  of  a  cat. 


214  ILLUSTRATIONS    OF    DISSECTIONS. 

Veins  accompany  the  arteries.  The  upper  laryngeal  opens  through 
the  superior  thyroid  vein  into  the  internal  jugular  trunk;  and  the  lower 
sends  its  blood  into  the  innominate  vein  along  the  inferior  thyroid  branch. 


THE  THYROID  BODY  AND  THE  TRACHEA. 

In  a  side  view,  the  thyroid  body,  T,  is  only  partly  visible.  This  organ  is 
larger  in  the  female  than  in  the  male,  and  is  more  developed  in  the  foetus 
than  in  the  adult  relatively  to  the  rest  of  the  body:  its  use  is  not  known. 

It  is  placed  opposite  the  upper  part  of  the  trachea;  and  consists  of 
two  lobes,  right  and  left,  which  are  firmly  attached  to  the  windpipe,  and 
project  upwards,  one  on  each  side,  as  far  as  the  thyroid  cartilage.  A 
narrow  part,  the  isthmus,  joins  the  lobes  beloAV  in  front  of  the  trachea. 
Each  lobe  is  pointed  above  and  wide  below;  and  it  lies  between  the  larynx 
and  the  common  carotid  artery,  where  it  is  covered  by  the  depressor  mus- 
cles of  the  hyoid  bone  (Plate  xxiv.). 

Projecting  upwards  from  the  left  lobe,  or  from  the  isthmus,  is  a  small 
tapering  part,  U — the  joyramid,  which  is  connected  to  the  os  hyoides  by 
a  band  of  fibrous  tissue.  Sometimes,  as  in  the  Drawing,  a  thin  muscular 
slip,  W,  levator  glandulm  thyroidem,  unites  the  pyramid  with  the  hyoid 
bone. 

Brownish  red  or  purplish  in  color,  it  consists  of  small  masses  or  lo- 
bules about  as  large  as  the  little  finger  nail.  It  does  not  joossess  any  ex- 
cretory duct.  On  cutting  into  it  a  thick  yellowish  fluid  escapes  from 
small  closed  capsules  or  vesicles. 

The  swelling  of  the  throat  known  as  a  wen  or  Derbyshire  neck,  is 
caused  by  enlargement  of  the  thyroid  body. 

Bloodvessels. — Two  large  arteries  on  each  side  ramify  in  this  body. 
The  upper  thyroid,  h,  a  branch  of  the  external  carotid,  enters  the  apex 
of  the  lobe,  but  it  distributes  some  branches  over  the  surface,  which  join 
the  other  arteries.  The  loiuer  thyroid,  k,  is  usually  larger  than  the  upper, 
and  is  a  branch  of  the  subclavian  trunk:  it  penetrates  the  base  of  the 
lobe,  and  offsets  ramify  over  the  under  surface.  All  the  arteries  commu- 
-i.icate  freely  together. 

Three  large  thyroid  veins  issue  on  each  side.  Two,  upper  and  lower 
thyroid,  run  with  the  arteries  of  the  same  name,  and  end — the  former  in 
the  internal  jugular,  and  the  latter  in  the  innominate  vein.     A  middle 


FIG. 


PLATE  XXV 


'  ^       ^       y  i# 


\  I' 


9^ 


••■^'S     £. 


"!      %^    V 


Y     ,  1 


FIG. 


FIG.  lit. 


^^^'")    i'^ 


A^^... 


k%^ 


El 


THE   TRACHEA.  215 

thyroid  vein  leaves  the  middle  of  the  lobe,  and  crossing  the  common  caro- 
tid artery  joins  the  internal  jugular  trunk. 

The  trachea  or  windpipe,  D,  reaches  from  the  larynx  to  the  thoraXj 
and  divides  in  that  cavity  into  two  pieces  or  bronchi — one  for  each  lung. 
Placed  in  front  of  the  oesophagus,  Z,  along  the  middle  line  of  the  body, 
it  is  round  and  firm  in  front,  but  flat  and  soft  behind,  and  is  always  per- 
vious to  the  air.  Its  transverse  width  is  about  an  inch  in  the  male,  but 
less  in  the  female.  Its  fore  and  hinder  parts  differ  much  in  their  compo- 
sition. 

The  firm  fore  part  of  the  tube  consists  of  dense  fibrous  membrane, 
which  incases  separate  pieces  of  cartilage  about  one-sixth  of  an  inch  wide, 
and  forming  three-fourths  of  a  circle.  Each  piece  has  its  convexity 
directed  forwards;  and  the  whole  keep  apart  the  walls  of  the  tube.  Be- 
hind, where  the  trachea  is  flattened,  it  is  constructed  by  fibrous  mem- 
brane (X,  Fig.  iii.)  continuous  with  that  containing  the  pieces  of  carti- 
lage; and  beneath  it  is  a  layer  of  transverse  muscular  fibres,  together  with 
some  superficial  bundles  of  short  longitudinal  fibres. 

Lining  the  trachea  is  a  mucous  membrane  covered  with  a  columnar 
and  ciliated  epithelium;  and  beneath  the  same  is  a  layer  of  elastic  tissue 
which  is  collected  into  bundles  in  the  flat  part  of  the  tube.  Many  glands 
are  placed  beneath  the  mucous  membrane;  and  the  largest  occupy  the 
back  of  the  windpipe,  where  some  are  external  to  the  fibrous  and  the 
muscular  layer. 


DESCRIPTION  OF  PLATE  XXVIII. 


These  three  Figures  of  vertical  sections  of  the  nose  will  indicate  the 
boundaries  of  that  cavity,  and  the  openings  into  it. 

For  Figure  i.,  the  right  half  of  the  nasal  cavity  was  cut  through  ver- 
tically, and  the  septum  nasi  was  removed — the  fore  part  of  the  skull  hav- 
ing beea  previously  d&taehed  for  the  dissection  of  the- pharynx. 

The  nose  was  sawed  through  on  the  left  of  the  septum  for  Figure  ii. ; 
and  pieces  of  the  middle  and  inferior  spongy  bones  were  cut  out  to  render 
evident  the  openings  into  the  meatuses. 

And  for  Figure  iii.  the  mucous  membrane  was  removed  trom  the  sep- 


216 


ILLUSTEATIONS    OF   DISSECTIONS. 


turn  nasi,  after  the  saw  had  been  carried  vertically  through  the  left  nasal 
fossa. 


BOUNDARIES  OF  THE  NASAL  CAVITY. 

Some  of  the  boundaries  appear  in  all  the  Figures,  and  the  same  letters 
of  reference  are  used  for  them. 


A.  Middle  part  of  the  roof  of  the 

nasai  fossa. 

B.  Fore  part  of  the  roof. 

C.  Back  of  the  roof. 

D.  Floor  of  the  nasal  cavity. 

E.  Dilatation  within  the  nostril. 

F.  Upper  spongy  bone. 

G.  Middle  spongy  cone. 
H.  Lower  spongy  bone. 

I.  Upper  meatus  of  the  nose. 
J.  Middle  meatus. 
K.  Lower  meatus. 
L.  Sphenoidal  sinus. 
M.  Frontal  sinus. 


N.  Funnel-shaped  prominence  of  the 

ethmoid  bone. 
O.  Aperture  of  the  nasal  duct. 
P.  Opening  of  the  Eustachian  tube. 
Q.  Soft  palate  cut  through. 
R.  Descending  plate  of  the  ethmoid. 
S.  Vomer. 

T.  Cartilage  of  the  septum. 
U.  Cartilage  of  the  aperture. 
V.  Pharynx. 

W.  Genio-hyo-glossus  muscle. 
X.  Epiglottis. 
Y.  Os  hyoides. 
Z.  Thyroid  cartilage. 


Each  half  of  the  nose  cavity  is  a  flattened  space,  which  communicates 
with  the  face  and  the  pharynx,  and  with  the  hollows  or  sinuses  in  the 
surrounding  bones.  It  intervenes  between  the  base  of  the  skull  and  the 
mouth,  and  occupies  the  interval  between  the  eye  sockets.  The  bones  of 
the  face  and  skull  enter  into  its  construction;  and  the  boundaries  are 
named  roof  and  floor,  inner  and  outer  wall. 

The  floor,  D,  is  horizontal  and  smooth;  and  its  bony  framework  con- 
sists of  the  palate  pieces  of  the  upper  maxillary  and  palate  bones. 

The  roof  reaches  from  the  nostril  to  the  posterior  naris,  and  is  sloped 
before  and  behind.  Its  centre  is  formed  by  the  thin  cribriform  plate  of 
the  ethmoid.  A,  and  is  nearly  straight;  the  fore  part  is  made  up  of  the 
frontal  and  nasal  bones,  and  the  lateral  cartilage;  and  the  hinder  part  is 
bounded  by  the  anterior  and  inferior  surfaces  of  the  body  of  the  sphenoid, 
with  the  sphenoidal  spongy  and  the  palate  bones. 

The  inner  wall  is  the  septum  or  partition  between  the  fossae  of  oppo- 
site sides.  In  it  are  the  descending  plate  of  the  ethmoid,  E,  the  vomer, 
S,  and  the  triangular  cartilage,  T. 

The  outer  wall  is  marked  by  projecting  osseous  pieces  with  subjacent 


BOUNDARIES    OF    THE    NASAL    CAVITY.  217 

hollows,  and  is  constructed  of  several  bones.  From  before  back  the 
following  is  the  order  of  succession,  viz. :  os  nasi,  upper  jaw,  lachrymal, 
ethmoid,  and  palate  bones,  with  the  internal  pterygoid  plate  of  the  sphe- 
noid bone.     Below  the  nasal,  in  front,  the  lateral  cartilage  is  found. 

The  width  of  the  nasal  fossa  is  larger  below  than  above;  and  at  the 
floor  close  to  the  septum  is  the  greatest  space  available  for  passing  an 
instrument  through  the  cavity.  Across  the  upper  part  of  the  fossa  the 
spongy  bones  project,  so  as  nearly  to  touch  the  septum.  From  before 
back  the  length  measures  about  three  inches  along  the  floor,  and  the 
depth  amounts  to  two  inches  at  the  centre. 

In  front  is  the  opening  called  the  nostril:  this  is  an  elongated  hole 
which  is  surrounded,  except  behind,  by  the  cartilage  of  the  aperture,  U, 
and  is  always  open.  For  the  distance  of  half  an  inch  within  the  nostril 
is  a  dilatation,  E,  large  enough  to  take  the  end  of  the  finger,  which  is 
lined  by  skin  provided  with  hairs  or  vibrissse.  Behind,  the  space  com- 
municates with  the  pharynx  by  the  posterior  naris  (Plate  xxvi.). 

In  breathing  the  air  passes  ordinarily  through  the  lower  half  of  the 
nasal  fossa,  but  by  sniffing,  as  in  the  attempt  to  recognize  faint  odors, 
the  current  can  be  directed  upwards  to  the  region  where  the  olfactory 
nerve  ramifies. 

Through  the  lower  part  of  the  nasal  fossa'  the  opening  of  the  Eusta- 
chian tube,  P,  can  be  reached.  To  enter  that  tube  an  instrument 
should  have  the  requisite  size  and  curve,  and  should  be  directed  along  the 
floor  close  to  the  septum  until  it  reaches  the  posterior  naris;  then  the 
point  is  to  be  turned  upwards  and  outwards  into  the  aperture.  In  like 
manner  a  flexible  tube  can  be  passed  through  the  cavity  to  the  pharynx 
for  the  purpose  of  conveying  liquid  food  into  the  stomach. 

Blood  escaping  into  the  nasal  cavity  from  rupture  of  the  vessels  of  the 
mucous  lining  requires  to  be  confined  within  the  space  when  the  loss  of 
a  fresh  quantity  may  be  injurious  to  health  or  endanger  life.  In  closing 
the  nasal  fossa  the  posterior  naris  is  stopped  first  by  a  plug  inserted 
through  the  mouth  in  the  following  manner; — An  elongated  dossil  of 
lint  or  cotton  wool  of  the  size  of  the  opening  is  to  have  a  piece  of  silk  or 
small  twine  tied  around  the  middle,  as  as  to  leave  the  ends  about  a  foot 
long.  Next,  a  bit  of  wire  (not  too  stiff),  with  a  noose  at  the  end  and 
rather  curved  downwards,  is  to  be  pushed  along  the  floor  of  the  nose  and 
behind  the  soft  palate  until  it  can  be  seen  through  the  open  mouth.  One 
of  the  string  ends  should  be  inserted  through  the  noose  with  a  pair  of 


218  ILLUSTEATIOJSrS    OF    DISSECTIONS. 

forceps,  the  other  being  retained  in  the  left  hand.  By  withdrawing  the 
wire  the  string  will  be  brought  out  through  the  nostril;  and  by  means  of 
that  piece  of  string  the  plug  can  be  dragged  through  the  mouth,  and 
round  the  soft  palate  Avith  the  aid  of  the  left  forefinger  to  the  posterior 
naris.  The  two  strings  may  be  then  tied  between  the  nose  and  mouth. 
Finally  to  complete  the  closure  of  the  nasal  cavity  the  nostril  is  to  have 
a  plug  inserted  into  it. 

When  the  surgeon  considers  the  bleeding  not  likely  to  return  the  plugs 
are  to  be  taken  away.  For  the  removal  of  the  anterior  one  the  proceed- 
ing is  simple;  but  the  posterior  has  to  be  taken  out  through  the  mouth 
in  this  way: — The  knot  on  the  face  being  untied,  the  plug  is  to  be  dis- 
lodged from  the  posterior  naris  by  pulling  downwards  and  backwards  with 
a  forceps  the  string  in  the  mouth;  and  it  is  then  to  be  conducted  round 
the  soft  palate  to  the  exterior  of  the  body. 

SPONGY  BONES    AND  THE  MEATUSES. 

Three  curved  bones.  Fig.  i.,  project  into  the  nasal  cavity  from  the 
outer  wall;  they  are  named  from  their  form  spongy  or  turbinate;  and 
froir  their  position,  upper,  middle,  and  lower.  These  osseous  pieces  do 
not  extend  the  whole  length  of  the  outer  wall,  but  are  confined  to  a  part 
limited  by  two  lines  continued  upwards — one  from  the  front  and  the 
other  from  the  back  of  the  hard  jialate. 

The  iqjjier  spongy  bone,  F,  is  a  process  of  the  lateral  mass  of  the  os 
ethmoides;  and  it  occupies  the  posterior  half  of  the  interval  before  men- 
tioned. 

The  middle  spongy  bone,  G,  is  also  a  process  of  the  ethmoid,  and 
forms  the  lower  curved  edge  of  the  lateral  mass  of  that  bone:  usually  it 
reaches  all  across  the  space  included  by  the  two  vertical  lines. 

The  inferior  spongy  bone,  H,  one  of  the  facial  bones,  is  larger  than 
the  others,  and  its  length  rather  exceeds  the  limits  of  the  space  referred 

to. 

The  spongy  bones  are  thin  and  brittle;  and  as  they  are  convex  on  the 
inner  surface  and  concave  on  the  outer,  channels  or  meatuses  exist 
between  them  and  the  wall  to  which  they  are  attached.  They  are  covered 
by  the  mucous  membrane,  and  afford  greater  surface  for  the  ramifications 
of  the  nerves  and  bloodvessels. 

The  meatuses  Fig.  i.,  are  the  lengthened  spaces  between  the  spongy 


THE    MUCOUS    MEMBRANE    AND    THE    BL00PVE8SP:L8.  219 

bones  and  the  outer  wall;  and  tlicy  are  the  same  in  number  as  those 
bones.  Occasionally  there  is  a  rudiment  of  a  fourth  space  above  the  rest, 
as  in  Fig.  ii. 

The  upper  meatus,  I,  less  deep  and  long  than  the  others,  communi- 
cates with  the  posterior  ethmoidal  cells  by  an  aperture  or  apertures  at  the 
fore  part  (Fig.  ii.). 

The 'middle  meatus,  J,  has  several  openings  in  it  from  hollows  in  the 
surrounding  bones;  and  in  Fig.  ii.  the  middle  spongy  bone  is  represented 
cut  through  to  show  the  apertures.  At  the  front  of  the  meatus  is  an 
elongated  eminence,  N,  of  the  ethmoid  bone,  with  two  grooves,  one 
before  and  the  other  behind  it:  the  anterior  groove  leads  upwards  into  the 
frontal  sinus,  M,  and  the  posterior  opens  into  the  anterior  ethmoidal 
cells.  Close  above  the  lower  part  of  the  prominence  referred  to,  and 
midway  between  the  letters  J  and  N,  is  the  small  round  hole  of  the 
antrum  maxillare. 

The  inferior  meatus,  K,  receives  the  ductus  ad  nasum;  and  to  see  this 
the  lower  spongy  bone  will  require  to  be  cut  through  in  front.  In  the 
dried  bone  the  canal  for  the  tears  has  a  wide  funnel-shaped  end  in  the 
meatus;  but  in  the  recent  state  a  piece  of  the  lining  membrane  of  the 
nose  is  stretched  over  the  aperture  forming  a  valve  for  it,  and  leaves  only 
a  small  oblique  passage  for  the  tears.  In  the  Figure  the  size  of  the  open- 
ing, 0,  is  to  be  seen.  Usually  the  flap  closes  the  aperture,  and  prevents 
air  from  being  driven  out  of  the  nose  into  the  lachrymal  canals.  An 
instrument  entering  the  duct  from  below  must  necessarily  injure  the 
valve. 

One  sinus,  viz.,  that  of  the  oody  of  the  sphenoid  bone,  L,  does  not 
open  into  a  meatus;  its  aperture,  which  is  rather  large,  may  be  seen  on 
the  slanting  hinder  part  of  the  roof. 


THE  MUCOUS  MEMBRA.NE  AND  THE  BLOODVESSELS. 

The  mucous  membrane,  named  jDituitary  and  Schneiderian,  clothes 
the  cavity,  uniting  with  the  periosteum  of  the  bones,  and  joins  the  skin 
in  front,  and  the  lining  of  the  pharynx  posteriorly.  It  is  continued  over 
the  foramina  transmitting  vessels  and  nerves  into  the  cavity,  so  as  to  close 
them;  but  it  sinks  into  the  apertures  leading  into  the  sinuses  in  the  sur- 
rounding bones,  and  lines  those  air  spaces,  whilst  it  diminishes  some- 
what the  size  of  their  openings.     Through  the  nasal  duct  it  is  continued 


220  ILLUSTRATIONS    OF    DISSECTIONS. 

upwards  to  tlie  lachrymal  sac,  and  forms  below  a  thin  Talve,  0,  which 
shuts  the  opening. 

In  the  lower  half  of  the  nasal  cavity  the  membrane  is  thick  and 
vascular,  particularly  over  the  septum  nasi  and  the  lower  spongy  bone; 
and  it  increases  the  surface  of  the  latter  by  being  prolonged  from  the 
lower  margin.  Its  epithelium  is  columnar  and  ciliated,  except  in  the 
dilatation  near  the  nostril  where  it  joins  the  epidermis  and  is  laminar:  at 
this  same  spot  it  is  provided  with  papillae,,  and  with  long  hairs  or  vibrissse. 
Large  mucous  glands  abound  in  the  lower  part  of  the  nose,  and  their 
apertures  cover  the  surface. 

In  the  upper  part  of  the  nose  the  mucous  layer  is  less  thick  and  vas- 
cular, and  is  of  a  yellowish  color.  Tlie  epithelium  is  thick,  especially 
over  the  olfactory  region,  and  is  laminar  according  to  Bowman;  though 
other  observers  state  that  it  is  ciliated  at  spots,  and  is  columnar.  The 
glands  are  numerous.  In  the  olfactory  region  these  resemble  the  sweat- 
glands  of  the  skin,  and  open  in  rows  between  the  nerve  branches:  their 
long  ducts  are  lined  by  scaly  epithelium. 

Bloodvessels. — As  the  arteries  are  not  injected,  suffice  it  to  say  that 
they  are  derived  chiefly  from  the  internal  maxillary,  and  come  through 
the  spheno-palatine  foramen.  A  few  enter  through  the  apertures  in  the 
roof  from  the  ophthalmic  artery,  and  near  the  nostril  are  branches  of  the 
facial.  In  the  pituitary  membrane,  they  form  a  network,  and  on  the 
surface  and  free  edges  of  the  two  lower  spongy  bones  they  ramify  in 
plexuses  beneath  the  membrane. 

The  veins  accompany  the  arteries,  and  form  large  venous  plexuses  on 
the  septum  nasi  and  the  middle  and  lower  spongy  bones.  Through  the 
apertures  in  the  cribriform  plate  of  the  ethmoid,  the  veins  of  the  nasal 
cavity  communicate  with  those  in  the  cranium. 

THE  OLFACTORY   REGION    AND  THE   NASAL    NERVES. 

In  the  mucous  membrane  at  the  top  of  the  nasal  cavity  the  olfactory 
nerve  ends,  and  the  seat  of  smelling  is  located.  To  this  part  the  term 
olfactory  region  has  been  applied  by  Mr.  Bowman.  Its  situation  is 
under  the  cribriform  plate  of  the  ethmoid  bone,  and  it  extends  down  for 
^bout  an  inch  on  the  septum  nasi  and  the  outer  wall. 

Over  the  limits  of  this  region  the  mucous  membrane  is  thin,  as  before 
said,  with  thick  scaly  epithelium,  and  the  glands  are  like  sweat-glands. 


THE    OLFACTORY    REGION    AND    THE    NASAL    NERVES.  221 

The  vessels  construct  a  network  in  tlie  adult,  but  in  the  foetus,  Mr.  Bow- 
man found  on  injecting  them  loops  here  and  there  with  enlargements, 
suggesting  to  him  the  idea  of  rudimentary  papillae. 

Olfactory  nerve. — The  offsets  of  the  olfactory  nerve  enter  the  nose 
through  the  foramina  in  the  cribriform  plate  of  the  ethmoid  bone,  and 
penetrating  the  mucous  membrane,  they  divide  and  subdivide  in  a  plexi- 
form  manner  till  they  are  reduced  to  the  necessary  degree  of  fineness, 
but  the  mode  of  ending  of  the  nerve-filaments  is  not  known.  Eecent 
researches  (Schultze)  point  to  the  ending  of  the  branches  in  olfactory  or 
nerve-cells,  which  resemble  somewhat  columnar  epithelium,  and  project 
to  the  free  surface  amongst  the  cells  of  the  epithelium.*  In  their  struc- 
ture the  nerve  fibrils  resemble  the  sympathetic  more  than  other  nerves, 
for  they  are  granular,  and  are  provided  with  oval  corpuscles,  which  become 
visible  on  the  addition  of  acetic  acid. 

Upon  this  nerve  the  faculty  of  recognizing  odors  depends.  In  ordi- 
nary breathing,  when  the  air  traverses  chiefly  the  lower  half  of  the  nasal 
cavity,  faint  odors  fail  to  give  indication  of  their  presence  ;  but  if  the  air 
is  carried  upwards  into  the  olfactory  region  by  sniffing,  the  odorous  par- 
ticles diffused  111  the  air  will  be  detected,  because  they  are  brought  more 
comi^letely  into  contact  with  the  nerves.  Touching  the  olfactory  region 
with  a  solid  body,  as  with  a  probe,  does  not  excite  the  sensation  of  smell. 
Disease  of  the  brain  sometimes  gives  origin  to  supposed  offensive  odors. 

Fifth  Nerve. — Through  the  following  offsets  of  the  first  and  second 
trunks  of  the  fifth  nerve  the  pituitary  membrane  is  supplied. 

The  nasal  nerve  of  the  ophthalmic  trunk  ramifies  in  the  fore  part  of 
the  cavity  from  the  roof  to  the  nostril,  and  acts  as  the  guardian  nerve  of 
the  anterior  opening  by  endowing  the  part  referred  to  with  great  sensi- 
bility. Irritation  of  the  anterior  portion  of  the  nasal  cavity  gives  rise 
through  this  nerve  to  the  reflex  act  of  sneezing,  with  the  view  of  dislodg- 
ing the  unusual  stimulus  by  a  strong  current  of  air  rapidly  expelled. 

The  spheno-palatine  branches  of  the  upper  maxillary  nerve  furnish 
offsets  through  Meckel's  ganglion  to  all  the  remainder  of  the  cavity ; 
these  branches  pass  for  the  most  part  through  the  spheno-palatine  fora- 
men. Common  sensibility  and  the  nutrition  of  the  mucous  membrane 
are  dependent  upon  this  trunk  of  the  fifth  nerve. 

*  Manual  of  Human  Microscopic  Anatomy.     By  A.  KoUiker.     Lend. ,  1860,  p. 
604.     In  this  work  reference  is  given  to  the  writings  of  Herr  Schultze. 


Illustrations  of  Dissections 


Mmcs  0f  ©riginal  ©olorjcd  glates 


THE    SIZE    OF    LIFE 


REPRESENTING  THE 


DISSECTION    OF    THE    HUMAN    BODY 


GEOEGE  VINER  ELLIS 

PROFESSOR    OF    ANATOJIT    IN    UNIVERSITY    COLLEGE,    LONDON 
AND 

G.  H.  FORD,  Esq. 


THE  DRAWINGS  ARE  FROM  NATURE  BY  MR  FORD,   FROM  DISSECTIONS 
BY  PROFESSOR  ELLIS. 

[Reduced  on  a  uniform  scale,  and  reproduced  in  facsimile,  expressly  for 
Wood's  Library  of  Standard  Medical  Authors.) 


^ztonCi  %Cixlxon 


TWO  VOLUMES  IN  ONE -VOLUME  IL 


NEW   YOBK 

WILLIAM    WOOD     &     COMPANY 

1891 


CONTENTS. 


THE   PEEIK^UM. 

Plate  XXIX. — Anatomy  op  the  posterior  half,  or  the  anal  part  of 

THE  perineum   in  THE  MALE 9 

End  of  the  rectum  with  its  muscles 9 

Ischio-rectal  fossa 13 

Bloodvessels  and  nerves  of  the  part 14 

First  stage  of  lithotomy .  15 

Plate  XXX. — Superficial  viEvy  of  the  anterior  or  urethral  half  of 

THE  MALE  PERINEUM 16 

Tube  of  the  urethra  with  its  muscles 16 

Superficial  perineal  vessels  and  nerves 20 

Accessibility  of  the  urethral  tube        .        .     '   .        .        .  21 

Plate  XXXI. — Deep  view  of  the  anterior  half  of  the  perin.^um  of 

THE  MALE 21 

Triangular  ligament  with  the  urethra  in  it         .        .        .  22 

Muscles  of  the  membranous  part  of  the  urethra    ...  23 

Pudic  vessels  and  their  deep  branches         ....  24 

Pudic  nerve  and  its  deep  branches 26 

Second  stage  in  the  operation  of  lithotomy         ...  26 


THE  ABDOMI^^AL  PAEIETES. 

Plate  XXXII.— First  view  of  the  abdominal  wall  in  the  inguinal 

region 27 

Superficial  fascia,  vessels,  and  glands 27 

Aponeurosis  of  the  external  oblique,  with  Poupart's  liga- 
ment and  the  abdominal  ring 29 

Cutaneous  vessels  and  nerves 32 

Plate  XXXIII.— Second  view  of  the  abdominal  wall  in  the  inguinal 

REGION 33 

Internal  oblique  and  cremaster  muscles      ....  33 

Iliac  branches  of  the  lambar  plexus 34 


4 


CONTENTS. 


PAGE 

Plate  XXXIV  — Third  view  of  the  abdominal  wall  in  the  inguinal 

REGION  ...                35 

Transversalis  muscle  and  fascia 36 

Abdominal  ring  and  spermatic  cord        .        .        .        .        .  36 

External  inguinal  hernia 38 

Congenital  and  infantile  varieties 42 

Internal  inguinal  hernia .  48 

Variety  of  internal  hernia 46 

Plate  XXXV. — Inner  view  of  the  wall  op  the  abdomen  in  the  in- 
guinal REGION 47 

Membranes  lining  the  abdominal  wall 48 

Abdominal  and  crural  rings          ......  49 

Anatomy  of  femoral  hernia,  in  part 51 

External  iliac  artery  and  branches 52 

Ligature  of  the  iliac  artery 53 

Plate  XXXVI. — Deep  Muscles  of  the  abdominal  parib:tes,  and  vessels 

OP  the  cavity 55 

Diaphragm,  and  muscles  of  the  loins 56 

Aorta,  and  inferior  cava,  with  their  branches    ...  60 

Nerves  of  the  parietes 64 

Plate   XXXVII. — Internal   iliac   artery,    and    lumbar   and    sacral 

PLEXUSES 65 

Parietal  branches  of  arteries,  and  the  internal  iliac  trunk    .  66 

Lumbar  plexus  and  branches 69 

Sacral  plexus  and  branches 71 

Lumbar  and  sacral  parts  of  the  cord  of  the  sympathetic       .  71 


THE   PELVIS. 

Plate  XXXVIII.— First  side  view  op  the  male  pelvis  with  the  mus- 
cles bounding  it  below 73 

Muscles  dosing  the  pelvic  outlet  laterally       ....  73 

Pudic  artery  and  some  offsets 75 

Pudic  nerve  and  its  offsets 76 

Plate  XXXIX  —Second  view  of  the  male  pelvis  showing  the  fascia 

IN  THE   interior 77 

Arrangement  of  the  recto- vesical  fascia         .        .        .        .78 


CONTENTS.  5 

PAGE 

Plate  XL.— Side  view  of  the  viscera  of  the  male  pelvis        .        .  80 

Connections  of  the  rectum 81 

of  the  ux'inary  bladder 82 

Ligaments  of  the  bladder 83 

Eecto-vesical  pouch  of  peritoneum 84 

Prostate  and  vesicula  seminalis 85 

Curve  of  the  male  urethra 86 

Third  stage  of  the  operation  of  lithotomy        ....  86 

Visceral  ai-teries  of  the  pelvis 88 

Nerves  of  the  pelvis  to  muscles  and  viscera    ....  89 

Plate  XLI. — Side  view  of  the  viscera  of  the  female  pelvis   .        .  90 

Connections  of  the  rectum 91 

bladder  and  urethra 91 

uterus  and  vagina         ......  92 

Peritoneum  and  its  pouches 93 

Appendages  of  the  uterus .94 

Visceral  arteries  of  the  pelvis        ......  95 

Visceral  nerves  of  the  pelvis 9^ 


THE   LOWER  LIMB. 

Plate  XLII. — The  superficial  parts  of  the  groin,   and  the  fascia 

lata  at  the  top  of  the  thigh        ....  97 

Superficial  vessels  and  nerves  and  glands        ....  98 

Fascia  lata  and  the  saphenous  opening       ....  99 

Plate  XLIII. — Anatomy  of  the  parts  concerned  in  femoral  hernia  102 

Crural  sheath,  with  the  crural  ring  and  canal        .        .         .  103 

Femoral  hernia  surgically  considered         ....  105 

Plate  XLIV.— Surface   view   of   the    thigh,    with    the    cutaneous 

nerves  and  vessels 108 

Superficial  nerves  and  vessels 108 

Scarpa's  triangular  space      .        .        .        .        .        .        .  HI 

Surface  view  of  the  superficial  muscles 113 

Plate  XLV  — Anatomy  of  the  femoral  vessels,  and   the   anterior 

crural  nerve       ...        r       ...       .  115 

Femoral  artery  and  vein  with  their  branches  ;  and  ligature 

of  the  ai'tery 115 

Anterior  crural  nerve  and  branches 120 


6  CONTENTS. 

PARE 

Plate  XLVI. — Deep  view  of  the  fore  and  outer  parts  of  the  thigh        122 
Muscles  on  the  front  of  the  thigh    .        .        .        .        .        .122 

External  circumflex  vessels  of  the  profunda      .        .        .         125 
Nerves  of  the  front  of  the  thigh 126 


Plate  XLVII. — Muscles  inside  the  femur  with  their  vessels   and 

NERVES 137 

Adductor  muscles  of  the  hip-joint 127 

Profunda  vessels  of  the  thigh 131 

Obturator  nerve  and  its  branches 133 

Plate  XLVIII. — First  stage  in  the  dissection  op  the  buttock  .        .  134 

Cutaneous  nerves  and  vessels 134 

Gluteus  maximus  muscle 136 

Plate  XLIX.— Second  stage  in  the  dissection  of  the  buttock  .       .  137 

Gluteus  medius,  and  external  rotators 137 

Superficial  arteries  of  the  buttock 141 

Superficial  nerves  of  the  buttock 143 

Plate  L. — Third  stage  in  the  dissection  of  the  buttock    ...  145 

Deep  muscles,  and  the  sacro-sciatic  ligaments        .        .        .  145 

Deep  arteries  of  the  buttock 148 

Deep  nerves  of  the  gluteal  region 150 

Plate  LI.— Common  view  of  the  popliteal  space  with  its  contents  ISl 

Form,  size,  and  boundaries  of  the  ham 151 

Situation  of  vessels  in  the  ham 153 

Nerves,  lymphatics,  and  fat  in  the  ham  .        .        .        .        .  155 

Plate  LII.— A  representation  of  the  back  of  the  thigh    .       .        .  156 

Muscles  behind  the  femur 156 

Vessels  at  the  back  of  the  thigh,  with  the'  popliteal  vessels  159 

Sciatic  and  popliteal  nerves 163 

Plate  LIII.— View  of  the  ham  undisturbed,  and  the  first  stage  of 

the  back  of  the  leg 166 

Cutaneous  nerves  of  the  leg,  behind 166 

Superficial  vessels  of  the  back  of  the  leg     .        .        .        .  167 

Muscles  of  the  calf,  and  natural  appearance  of  the  ham        .  169 


CONTENTS.  7 

PAGE 

Plate  LIV. — Deep  muscles  of  the  calf,  and  the  popliteal  vessels  and 

NERVES 171 

Soleus  and  plantaris  muscles 171 

Lower  end  of  the  popliteal  vessels 173 

Deep  branches  of  internal  popliteal  nerve       .        .  ,     .        .  175 

Plate  LV. — Deep  dissection  op  the  back  of  the  leg   .       .       ,       .  176 

Deep  muscles  behind  the  leg-bones 176 

Posterior  tibial  vessels,  with  wounds,  and  ligature  of  the 

artery 179 

Posterior  tibial  nerve .         .  183 

Plate  LVI. — First  and  second  stages  in  the.  examination  of  the  sole 

OF  the  foot 184 

Fig.  i.  First  layer  of  muscles .  185 

Superficial  arteries  of  the  sole       ...,.,  187 

Plantar  nerves .  189 

Fig.  ii.  Second  layer  of  foot-muscles        .        .        .        .        .         .  191 

Course  of  the  external  plantar  artery  and  nerve    .        .        .  198 

Plate  LVII. — Third  and  fourth  stages  of  the  dissection  op  the  sole 

of  the  foot 195 

Fig,  i.  Short  muscles  of  the  great  and  little  toes,  forming  the  third 

layer '195 

External  plantar  nerve  and  branches 197 

External  plantar  artery 198 

Fig.  ii.  Interossei  muscles,  and  tendons  of  the  tibialis  posticus  and 

peroneus  longus .        .  199 

Plantar  arch,  and  ending  of  the  dorsal  artery  of  the  foot      ,  201 

Plate  LVIII.— Front  of  the  leg  and  dorsum  of  the  foot  .       .       .  204 

Cutaneous  veins  and  arteries 204 

Cutaneous  nerves  of  the  leg  and  foot 205 

Muscles  of  the  front  of  the  leg  and  foot 207 

External  lateral  muscles  of  the  leg 211 

Anterior  tibial  vessels,  and  wounds  and  ligature  of  the  artery  212 

Anterior  tibial  and  musculo-cutaneous  nerves       .       .        .  216 


J    i 


PLATE  XXiX 


M\ 


ILLUSTRATIONS    OF    DISSECTIONS. 


ILLUSTRATION'S  OF  THE  PERINEUM. 


DESCRIPTION  OF  PLATE  XXIX. 


This  Figure  illustrates  tne  dissection  of  the  posterior  part  of  the  peri- 
neum. 

Boundaries  of  the  perincewn. — The  perinaeal  space  corresponds  with  the 
outlet  of  the  pelvis.  It  is  limited  in  front  by  the  symphysis  pubis, 
behind  by  the  tip  of  the  coccyx  with  the  great  gluteal  muscles,  and  on 
each  side  by  the  ]3ubic  arch,  and  by  the  great  sacro-sciatic  ligament 
covered  by  the  gluteus. 

Depth. — The  perinseum  reaches  into  the  pelvis  as  far  as  the  recto-vesi- 
cal  fascia,  which  forms  the  partition  between  the  perinaeum  and  the  joel- 
vic  cavity  (Plate  xxxix.),  and  as  this  septal  piece  of  fascia  is  directed 
obliquely  downwards  and  inwards,  the  measurements  to  it  from  the  sur- 
face of  the  body  will  vary  at  different  spots.  In  front,  near  the  jiubes, 
the  depth  of  the  space  is  about  an  inch,  but  it  amounts  behind  to  three 
inches  by  the  side  of  the  rectum. 

Division  mto  tivo. — In  this  region,  as  above  defined,  are  contained  in 
the  male  the  excretory  tubes  for  the  feces  and  urine.  A  transverse  line 
half  an  inch  in  front  of  the  anus  divides  it  into  two,  viz.,  a  posterior  or 
rectal,  and  an  anterior  or  urethral  part. 


POSTERIOR  PART  OF  THE   PERIN^XBI. 

In  the  hinder  part  of  the  peringeum  lies  the  rectum,  but  as  the  gut 
does  not  occupy  all  the  space  between  the  bones,  there  is  a  hollow  on  each 
side,  the  ischio-rectal  fossa,  which  is  filled  with  fat,  and  contains  some 


10  ILLUSTRATIONS    OF    DISSECTIONS. 

vessels  and  nerves.  On  the  left  side,  the  boundaries  of  the  space  may  be 
defined,  and  on  the  right,  the  vessels  and  nerves  may  be  brought  into 
view,  as  in  the  Plate. 

To  begin  the  dissection,  raise  the  slvin  from  the  posterior  part  of  the 
space  by  means  of  a  transverse  cut  at  the  front  of  the  anus,  and  of  a  lon- 
gitudinal one  carried  backwards  from  the  other,  around  the  anus  to  the 
coccyx.  From  the  front  and  back  of  the  sphincter  surrounding  the  anus  a 
fleshy  slip  is  to  be  followed  on  each  side  into  the  subcutaneous  fatty  layer. 

Next  remove  the  fat  and  the  small  vessels  and  nerves  from  the  ischio- 
rectal fossa  on  the  left  side,  and  then  trace  in  the  right  hollow  the  small 
vessels  and  nerves,  as  m  the  Figure. 

Rectum.  About  the  lower  three  inches  of  the  large  intestine  is  con- 
tained in  the  perinaeum.  This  part  of  the  gut  rests  on  the  end  of  the 
sacrum  and  on  the  coccyx.  Whilst  the  rectum  touches  the  bones,  it  is 
straight  in  its  direction,  but  at  the  end  of  the  spinal  column  it  is  bent 
backwards,  and  ends  at  the  surface  in  the  anal  aperture.  It  is  not  of 
uniform  size,  for  at  the  anus  it  is  narrowed  much  by  the  sphincter  mus- 
cles, but  an  inch  higher  it  is  swollen  into  a  sinus.  This  dilatation  is 
enveloped  by  the  levator  ani  muscle,  C,  on  each  side. 

Commonly,  there  are  rounded  swellings  of  a  bluish  color  projecting 
from  the  interior  of  the  gut,  which  are  denominated  internal  piles  or 
hsemorrhoids  ;  these  are  formed  out  of  dilated  veins  in  this  manner: 
Within  the  internal  sphincter  the  middle  h£emorrhoidal  arteries  and  veins 
form  loops  around  the  intestine  under  the  mucous  membrane,  having  an 
arrangement  peculiar  to  this  part  of  the  alimentary  passage.*  From 
time  to  time  parts  of  these  loops  become  dilated,  and  in  this  state  they 
form  small  tumors,  which  are  forced  down,  together  with  the  mucous 
membrane,  through'  the  sphincter  by  the  straining  efforts  to  expel  the 
contents  of  the  rectum,  and  they  carry  with  them  some  of  the  inter- 
mingled arterial  loops.  After  a  still  longer  interval,  the  canal  of  the 
vein  becomes  obliterated  by  a  solidified  fibrinous  clot,  and  the  submucous 
areolar  tissue  outside  becoming  thickened,  the  whole  forms  a  firm,  dense, 
fleshy-looking  mass.  Of  course,  the  number  and  size  of  the  piles  will  be 
proportioned  to  the  enlargement  of  the  veins  and  the  extent  to  which  the 


The  arrangement  of  these  vessels  and  their  disposition  in  haemorrhoids  have 
been  delineated  in  a  Work  on  Diseases  of  the  Rectum,  by  Richard  Quain,  F,R.S. 
Lond.,  1854. 


,    MUSCLES    OF    THE    RECTUM.  11 

loops  have  descended.  If  their  removal  is  desired,  some  means,  such  as 
ligature,  Avhich  would  arrest  the  flow  of  blood,  should  be  had  recourse  to, 
for,  as  the  veins  arc  deprived  of  valves,  the  swellings  should  not  be  cut 
off,  because  the  ends  of  the  arterial  and  venous  loops  would  then  remain 
open  to  bleed  into  the  intestine. 

Muscles  of  the  rectum.  Three  muscles  surround  the  lower  end  of  the 
intestine,  and  are  employed  in  diminishing  its  opening.  A  fourth  ele- 
vates and  constricts  the  gut. 


A.  Sphincter  ani  internus. 

B.  Sphincter  ani  externus. 

C.  Corrugator  cutis  ani. 


D.  Levator  ani. 

E.  Gluteus  maxinius. 


The  internal  splimcter,  A,  is  a  narrow  band  of  pale  circular  fibres 
around  the  extremity  of  the  rectum,  which  is  continuous  with  the  cir- 
cular fibres  of  the  gut.  About  a  quarter  of  an  inch  in  width  at  the  sur- 
face, it  is  distinct  from  the  external  sphincter,  B;  and  on  the  intestine 
it  extends  downwards  half  an  inch,  joining  the  muscular  coat  of  that  tube. 

This  muscle  assists  in  closing  the  anus,  and  its  action  on  that  aperture 
is  involuntary. 

Corriigator  cutis  ani,  C. — Superficial  to  the  internal  sphincter  is  a 
thin  stratum  of  involuntary  muscular  fibres  to  which  I  have  given  the 
above  name.*  This  subcutaneous  layer  extends  around  the  anus,  but 
only  a  part  on  the  right  side  has  been  delineated.  I  begins  rather  exter- 
nal to  the  preceding  sphincter;  and  the  fibres  converging  enter  the  anus, 
and  end  in  the  submucous  tissue  inside  the  internal  sphincter.  It  forms 
a  thin  layer  around  the  anus,  Avhich  is  closely  united  to  the  skin. 

When  the  fibres  contract  they  corrugate  the  skin  around  the  anus, 
throwing  it  into  lines  radiating  from  the  aperture. 

The  external  sphincter,  B,  surrounds  the  end  of  the  rectum  with  a 
thin  muscular  layer  about  an  inch  in  width,  which  is  fixed  in  front  and 
behind.  The  hinder  part  is  attached  by  fibrous  tissue  to  the  back  of  the 
coccyx  near  the  tip,  and  blends  largely  with  the  subcutaneous  areolar 
tissue  on  each  side:  in  the  Figure  this  part,  which  is  not  always  very 
evident,  has  been  cut  and  reflected.  In  front,  where  the  muscle  is  also 
wide,  it  is  inserted  into  the  central  point  of  the  perinseum,  and  on  each 
side  it  joins  the  subcutaneous  fatty  layer  by  a  rather  wide  slip. 

*  This  muscle  was  noticed  by  me  in  1854.     I  have  not  found  hitherto  any 
reference  to  it  in  works  of  Anatomy.     It  is  constantly  present. 


12  ILLUSTRATIONS    OF    DISSECTIONS. 

This  muscle  sliuts  the  anus  and  raises  the  skin  around  that  opening. 
Through  the  close  union  of  this  muscle  and  the  corrugator  with  the  der- 
mis, every  alteration  in  the  condition  of  their  fibres  is  accompanied  by 
movement  of  the  skin;  and  so  ulcers  near  the  anus  become  very  painful. 
Before  rest  can  be  obtained  and  the  healing  process  established,  the  mus- 
cular fibres  require  oftentimes  to  be  divided.  Ordinarily  the  muscle  is 
kept  in  a  state  of  contraction  through  the  influence  of  the  spinal  cord, 
and  it  is  relaxed  only  at  the  time  of  passing  the  feces;  but  there  exists 
also  some  voluntary  power  over  the  action  of  the  muscle.  When  the 
spinal  cord  is  injured  this  sphincter  passes  from  a  tonic  state  to  one  of 
paralysis;  and  in  long-continued  exhaustive  disease,  as  fever,  it  may  be- 
come powerless,  so  as  to  allow  of  the  feces  escaping  involuntarily. 

The  levator  ani,  D,  forms  with  the  muscle  of  the  oj)posite  side  a  fleshy 
diaphragm  in  the  outlet  of  the  pelvis.  It  is  attached  above  to  the  inner 
surface  of  the  os  innominatum — partly  to  bone  and  partly  to  the  recto- 
vesical fascia  and  the  triangular  ligament  (Plate  xxxviii.).  The  fibres 
descending  are  inserted  into  the  tip  of  the  coccyx;  into  the  side  of  the 
rectum,  blending  with  the  sphincter;  and  before  and  behind  the  gut  the 
muscles  of  opposite  sides  are  joined.  The  fleshy  stratum  formed  by  the 
two  muscles  closes  the  outlet  of  the  pelvis  behind  the  triangular  ligament, 
and  is  convex  downwards:  through  it  the  rectum  is  transmitted.  Its 
under  surface  looks  to  the  ischio-rectal  fossa,  and  the  upper  touches  the 
recto-vesical  fascia.  The  origin  of  the  muscle  is  best  seen  in  the  Plate 
of  the  side  view  of  the  pelvis  above  referred  to. 

The  chief  action  of  the  muscle  is  to  raise  and  restore  to  its  place  the 
lower  end  of  the  rectum  after  this  has  been  j)rotruded  in  defecation.  It 
sujoports  also  the  pelvic  viscera,  and  raises  and  compresses  the  tube  of  the 
urethra  by  its  anterior  fibres. 

Iscldo-rectal fossa.  This  hollow  is  so  called  from  its  position  between 
the  hip-bone  and  the  rectum.  Its  extent  on  the  surface  of  the  body  is 
marked  by  a  line  opposite  the  tip  of  the  coccyx  in  one  direction,  and  the 
fore  part  of  the  anus  in  the  other.  After  dissection  it  appears  as  a  some- 
what conical  interval,  which  is  wide  behind  and  narroAV  before,  and  de- 
creases in  breadth  as  it  sinks  into  the  pelvis.  From  before  back  it 
measures  about  two  inches.  Along  the  side  of  the  pelvis  its  depth  reaches 
two  inches.     Across  it  is  about  an  inch  wide  under  the  integuments. 

Its  outer  boundary  is  vertical,  and  consists  of  the  pelvis  with  the  in- 
ternal obturator  muscle  covered  by  fascia.     The  inner  wall,  very  oblique, 


ISCHIO-KECTAL   FOSSA.  13 

is  formed  by  the  levator  ani,  D,  and  the  external  sphincter,  B;  this  sur- 
face is  covered  by  a  thin  fascia.  In  front  is  the  triangular  ligament  of 
the  pcrinteum.  Behind  lies  the  gluteus  maximus,  E;  and  deeper  still  is 
the  sacro-sciatic  ligament. 

Vessels  and  nerves  pass  through  the  space.  On  the  outer  wall  lies  the 
internal  pudic  artery,  a :  it  is  contained  in  a  sheath  of  fascia,  which  keeps 
it  in  place;  and  it  is  accompanied  by  two  veins  and  the  pudic  nerve. 
Posteriorly  tlie  vessel  is  placed  about  one  inch  and  a  half  from  the  sur- 
face of  the  pubic  arch,  bat  towards  the  front  of  the  fossa  only  half  an  inch 
from  the  edge  of  the  bone.  Crossing  the  space  (left  side)  from  the  pudic 
trunks  are  the  inferior  hsemorrhoidal  vessels,  b,  and  the  mferior  hsemor- 
rhoidal  nerve,  3,  which  distribute  branches  to  the  lower  end  of  the  gut. 
At  the  front  of  the  hollow,  close  to  the  outer  wall,  lie  the  two  superficial 
perinseal  nerves,  1  and  2,  with  the  superficial  perinaeal  artery  sometimes: 
these  pass  forwards  to  the  anterior  half  of  the  perinaeum.  Behind,  near 
the  coccyx,  another  small  nerve,  5,  may  be  recognized:  this  is  an  offset 
from  the  fourth  sacral  to  the  extremity  of  the  rectum  and  the  teguments. 
"Winding  round  the  border  of  the  gluteus  maximus  at  the  back  of  the 
space,  are  superficial  branches  of  the  sciatic  vessels  and  nerve. 

A  granular  fat  fills  the  hollow  and  supports  the  gut.  Its  deficiency 
in  emaciated  bodies  causes  a  surface- depression  on  the  side  of  the  anus. 
Abscesses  are  prone  to  form  in  it,  which  manifest  a  striking  tendency  to 
leave  sinuses  or  fistulas  behind  them.  The  different  conditions  of  these 
sinuses  have  received  special  names.  If  a  sinus  opens  into  the  lower  part 
of  the  gut  as  well  as  on  the  skin,  having  thus  an  inner  and  an  outer  ori- 
fice, it  is  said  to  be  a  complete  fistula.  Supposing  the  abscess  to  discharge 
its  contents  on  the  surface  of  the  body  in  the  usual  way,  the  sinus  remain- 
ing is  named  an  incomplete  external  fistula;  and  if  it  bursts  into  the  gut 
through  the  inner  boundary  of  the  ischio-rectal  fossa  without  opening  ex- 
ternally, the  passage  remaining  is  called  a  blind  internal  fistula.  When 
abscesses  enter  the  gut  they  pierce  the  levator  ani  and  the  intestinal  wall, 
and  usually  at  a  spot  about  an  inch  from  the  anus.  These  burrowing 
passages  need  to  be  laid  open  before  they  will  head,  like  sinuses  in  the 
groin;  and  in  slitting  with  a  knife  those  that  pierce  the  gut,  tlie  levator 
ani,  the  external  sphincter,  and  the  intestine,  will  have  to  be  divided.* 

*  Mr.  Marshall  has  proposed  that  these  sinuses  should  be  cauterized  by  a  wire 
heated  by  galvanism,  with  the  view  of  preventing  secondary  haemorrhage.  See 
a  paper  in  Vol.  xxxiv.  of  the  Transactions  of  the  Roy.  Med.  Chir.  Society. 


14 


ILLUSTKATIONS    OF   DISSECTIONS. 


Bloodvessels  of  the  posterior  2Mrt  of  theperinmum.  The  small  arteries 
and  veins  supplying  the  lower  end  of  the  rectum,  are  derived  from  the  pudic. 
Some  others  are  distributed  to  the  integuments  by  the  sciatic  vessels. 


a.  Pudic  artery. 

h.  Inferior  haemorrhoidal. 


c.  A  second  lisemorrhoidal  branch. 

d.  Branches  of  the  sciatic. 


The  pudic  artery,  a,  an  offset  of  the  internal  iliac  in  the  pelvis,  enters 
the  perinaeum  through  the  small  sacro-sciatic  notch,  and  ascends  through 
this  region  to  end  in  the  i3enis  or  the  clitoris,  according  to  the  sex.  In 
tlie  hinder  part  of  its  course  the  vessel  lies  in  the  ischio-rectal  fossa,  and 
gradually  becomes  more  sujperficial  in  front,  as  before  said.  It  is  accom- 
panied by  two  veins,  by  the  trunk  of  the  pudic  nerve  which  is  deeper  than 
it,  and  by  the  perinseal  branch  of  the  same  nerve  v/hich  is  nearer  the  sur- 
face: the  anterior  part  of  the  vessel  appears  in  Plate  xxxi.  In  this  part 
of  its  course  it  gives  the  following  branch  to  the  rectum. 

The  inferior  licemorrlioidcd  artery,  h,  crosses  the  centre  of  the  ischio- 
rectal fossa,  and  divides  near  the  gut  into  branches  for  the  supply  of  the 
muscles,  the  integuments,  and  the  fat.  One  or  two  of  its  offsets  run  for- 
wards to  the  teguments  m  front  of  the  ischio-rectal  fossa.  The  artery 
may  be  represented  by  two  pieces,  as  in  the  Plate. 

Pudic  veins.  Two  veins  accompany  the  pudic  artery,  and  they 
receive  from  the  ischio-rectal  fossa  small  veins,  which  are  companion 
branches  of  the  haemorrhoidal  artery. 

Sciatic  artery.  Branches,  d,  of  this  artery  come  to  the  surface  round 
the  gluteus:  most  of  them  end  in  the  integuments,  but  some  enter  the 
muscular  fibres.     Veins  run  with  the  arteries. 

Nerves  in  the  posterior  part  of  the  perinceum.  Nerves  from  three 
sources,  viz.,  the  sacral,  pudic,  and  small  sciatic,  are  met  with  in  the 
ischio-rectal  fossa. 


1.  Anterior  superficial  perinseal. 

2.  Posterior  superficial  perinaeal. 

3.  Inferior  haemorrhoidal. 


4.  Branches  of  the  small  sciatic. 

5 .  Branch  of  the  fourth  sacral. 

6.  Branches    of     the    lower    sacral 

nerves. 


The  joz^cZic  nerve  is  a  branch  of  the  sacral  plexus,  and  accompanies  the 
artery  of  the  same  name,  distributing  offsets  like  it  for  the  most  part. 
In  the  posterior  half  of  the  perinaeum  the  nerve  lies  deeper  than  the 
artery  (Plate  xxxi.),  and  furnishes  the  two  following  branches: — 


HiEMORRHOIDAL    VESSELS    AND    NERVES.  15 

The  inferior  hmmorrhoidal,  3,  runs  with  the  artery  of  the  same  name 
across  the  ischio-rectal  fossa,  and  ends  in  the  external  sphincter  muscle 
and  the  inteo^uments:  some  offsets  are  directed  forwards  to  the  fore  part 
of  the  pcrinjKum. 

The  pcrincBal  branch  of  the  pudic,  of  larger  size  than  the  piece  of  the 
trunk  continued  to  the  penis,  furnishes  all  the  remaining  nerves  of  the 
peringeum.  It  begins  about  half  way  along  the  fossa,  and  becoming 
superficial  to   the   artery  splits   into   cutaneous,  muscular,  and  genital 

offsets: — 

Only  the  two  cutaneous  offsets  are  now  dissected  in  part:  they  are 
named  superficial,  pcrinteal,  anterior,  1,  and  posterior,  2,  and  are  con- 
tained for  a  short  space  in  the  ischio-rectal  fossa,  as  they  course  forwards 
to  end  in  the  scrotum. 

Sacral  nerves.  A  branch  of  the  fourth  sacral  nerve,  5,  pierces  the 
fibres  of  the  levator  ani  near  the  tip  of  the  coccyx,  and  is  distributed  to 
the  external  sphincter  and  the  integuments. 

Altoo-ether  behind  the  ischio-rectal  fossa  one  or  two  other  small 
branches  of  the  sacral  nerves  will  appear  (according  to  the  extent  of  the 
dissection)  by  the  side  of  the  coccyx:  they  pierce  the  fibres  of  the  gluteus 
maximus,  and  ramify  in  the  integuments. 

Small  sciatic  nerve.  Cutaneous  branches,  4,  of  this  nerve  wind  round 
the  largest  gluteal  muscle  to  reach  the  integuments  near  the  sacrum  and 
coccyx. 

In  the  posterior  half  of  the  perinaeum  the  first  incisions  in  the  lateral 
operation  of  lithotomy  arc  begun.  With  the  view  of  opening  a  way  down 
to  the  urethra,  and  of  securing  an  aperture  in  the  integuments  large 
enough  for  the  free  use  of  the  forceps  and  the  extraction  of  the  stone, 
the  operator  sinks  his  knife  through  the  skin  just  in  front  of  the  anus, 
and  carries  it  downwards  and  backwards  as  far  as  midway  between  the 
anus  and  the  ischial  tuberosity.  In  this  first  stage  of  the  operation  the 
knife  should  be  kept  in  the  middle  of  the  ischio-rectal  fossa,  and  should 
be  made  to  penetrate  more  deeply  behind  than  in  front.  Necessarily 
the  hfemorrhoidal  vessels  and  nerves  crossing  the  fossa  must  be  cut  as  the 
hollow  is  laid  open.  If  the  incision  in  the  skin  is  too  near  the  anus  the 
rectum  may  be  cut,  and  if  it  is  taken  close  to  the  bone  externally  the 
pudic  artery  may  be  injured.  In  the  usual  adult  state  of  t-he  parts  the 
pudic  vessels  cannot  well  be  reached;  but  in  a  child  in  whom  the  bones 


16  ILLUSTRATIONS    OF   DISSECTIONS. 

are  undeveloped,  or  in  a  man  with  a  very  narrow  pelvic  outlet,  the  artery- 
might  be  wounded  at  the  fore  part  of  the  fossa,  where  it  becomes  much 
more  superficial.  The  rectum  will  usually  remain  untouched  in  the 
living  body,  supposing  it  to  have  been  previously  freed  from  its  contents, 
by  pressing  it  inwards  away  from  the  scalpel  with  the  fore  finger  of  the 
left  hand. 

Within  a  distance  of  three  inches  from  the  anus  the  gut  may  be  cut, 
where  disease  renders  an  operation  necessary,  without  fear  of  passing  the 
limits  of  the  perineum,  and  entering  the  cavity  of  the  pelvis.  Should 
the  lower  end  of  the  rectum  be  removed  the  sphincters  and  levator  ani 
would  be  destroyed,  and  an  inability  to  control  the  passing  of  the  feces 
would  necessarily  follow  such  an  operation. 


DESCRIPTION  OF  PLATE  XXX. 


The  superficial  fascia,  with  muscles,  vessels,  and  nerves  of  the  anterior 
half  of  the  perineum,  are  delineated  in  this  Figure. 

Supposing  this  dissection  follows  that  in  Plate  xxix.,  it  may  be  exe- 
cuted by  raising  laterally  the  skin  by  means  of  a  central  longitudinal  in- 
cision from  the  scrotum  to  a  transverse  cut  in  front  of  the  anus.  For  the 
reflection  of  the  subcutaneous  fatty  layer  air  should  be  blown  beneath  it, 
on  each  side,  by  means  of  a  blow-pipe  inserted  through  it  at  the  fore  part 
of  the  ischio-rectal  fossa;  and  then  an  incision  should  be  made  through 
the  fat  along  the  track  of  the  air. 

On  the  left  side  throw  outwards  the  fatty  layer  to  show  its  hinder 
and  lateral  attachments,  and  a  membraniform  layer  on  the  under  surface; 
but  the  part  extending  on  to  the  thigh  may  be  taken  away  down  to  the 
fascia  lata,  as  in  the  Drawing.  On  the  right  side  the  superficial  pcrinasal 
vessels  and  nerves  are  to  be  traced  out  as  the  superficial  fascia  is  reflected. 

When  the  fatty  layer  has  been  examined  it  may  be  partly  removed  on 
both  sides  for  the  display  of  the  muscles.  , 


•  -■•^'ii',  ' .  i.v  . 


PLATE  XXX 


\// 


ANTERIOR    I'AKT    OF    THE    PERINEUM.  IT 


ANTERIOR  PART  OF  THE  PERINEUM. 

This  i^art  of  the  perinseal  space  is  placed  anterior  to  a  lino  lialf  an  incli 
in  front  of  the  anus.  It  lodges  the  tube  of  the  urethra,  and  the  roots  of 
the  penis  Avith  their  appertaining  muscles,  vessels,  and  nerves.  Com- 
monly its  form  is  an  equilateral  triangle,  and  its  sides  measures  three 
inches.  Its  boundaries  have  been  detailed  (p.  9).  All  the  parts  in- 
cluded in  this  space  are  covered  by  the  subcutaneous  fatty  layer  described 
below. 

The  stqjerficial  fascia,  G,  clothes  the  body  under  the  skin,  and  is 
directly  continuous  with  the  same  layer  in  the  scrotum  and  on  the  thighs; 
but  as  it  is  continued  into  the  scrotum  it  loses  its  fat,  and  acquires  in- 
voluntary muscular  fibres,  forming  therewith  a  contractile  tissue  (dar- 
tos). 

Over  the  fore  part  of  the  perinseal  space  the  fascia  possesses  a  mem- 
branous layer  on  the  under  surfac,  which  is  indicated  in  the  Plate,  and 
has  the  following  connections: — Externally  it  is  fixed  into  the  margin  of 
the  hip-bone  outside  the  crus  penis.  Behind,  it  bends  down  at  the  back 
of  the  transversalis  muscle,  to  be  united  witli  the  triangular  ligament  of 
the  urethra.  And  in  front  it  is  continued  into  the  scrotum  without  being 
connected  with  any  subjacent  part.  Attached  thus  on  the  sides  and  be- 
hind, it  arches  over  the  space  containing  the  urethral  tube  and  the  mus- 
cles. From  its  under  surface  some  areolar  tissue  projects  downwards 
opposite  the  urethra,  and  forms  a  partition  between  the  right  and  the  left 
side:  this  is  a  complete  septum  behind,  but  is  incomplete  in  the  scrotum 
where  it  is  pervious  to  air  or  fluid. 

The  space  thus  included  by  the  attachments  of  the  superficial  fascia 
opens  into  the  scrotum  in  front,  and  is  partly  subdivided  behind.  When 
air  is  blown  under  the  fascia  it  passes  forwards  on  the  sa::io  side  as  far  as 
the  median  septum  is  complete,  and  it  then  diffuses  itself  in  the  scrotum; 
but  if  more  air  is  still  forced  in  on  the  same  side  it  will  move  backwards 
froin  the  scrotum  along  the  opposite  side  of  the  perinseum.  When  urine 
finds  its  way  into  the  fore  part  of  the  perinseum  through  an  aperture  in 
the  urethra  it  is  directed  forwards  through  the  scrotum,  like  the  air,  by 
the  attachments  of  the  superficial  fascia  on  the  sides  and  behind. 

Tube  of  the  urethra.     In  the  side  view  of  the  male  pelvis  (Plate  XL.) 


18  ILLUSTRATIONS    OF    DISSECTIONS. 

this  tube  may  be  seen  to  extend  from  tlie  bladder  to  tbe  end  of  tlic  penis. 
In  its  course  it  passes  through  the  triangular  ligament  of  tlie  urethra,  and 
is  divided  by  that  structure  into  three  parts:  a  posterior  or  prostatic,  an 
anterior  or  spongy,  and  a  middle  or  membranous  which  is  contained  in 
the  ligament. 

The  spongy  portion,  which  occupies  the  anterior  half  of  the  perineal 
space,  lies  in  the  midline  of  the  body,  and  gives  rise  to  a  prominence 
under  the  central  ridge  or  raphe  of  the  skin.  Altogether  behind  it  is 
placed  an  inch  from  the  pubes  and  from  each  hip-bone;  and  after  an  ex- 
tent of  two  inches  it  is  applied  to  the  under  part  of  the  penis.  For  a 
distance  of  about  two  inches  it  is  covered  by  a  voluntary  muscle. 

Muscles  of  the  uretlira  andi)enis.  In  the  fore  part  of  the  perinseum 
there  are  superficial  and  deep  muscles.  The  superficial  layer  is  repre- 
sented in  this  Plate,  and  consists  of  three  on  each  side:  two  of  these,  C, 
and  D,  are  connected  with  the  tube  of  the  urethra,  and  one,  F,  belongs 
to  the  penis.  Between  the  urethra  and  the  penis  is  a  tendinous  point — 
central  point  of  the  peringeum,  in  which  the  muscles  blend. 


A.  Sphincter  ani  externus. 

B.  Levator  ani. 

C.  Transversalis  perinsei. 


D.  Ejaculator  urinse. 

E.  Gluteus  maximus. 

F.  Erector  penis. 


The  central  point  of  the  ijerinmum  shows  best  in  Plate  xxxi.  It  is  a 
firm  white  spot,  lying  nearly  in  the  centre  of  the  pelvic  outlet,  which 
serves  as  a  fixed  point  for  the  attachment  of  the  urethral  and  rectal  mus- 
cles. On  the  surface  of  the  body  it  corresponds  Avith  a  point  half  an  inch 
in  front  of  the  anus. 

The  transversalis perincBi  muscle  C,  lies  obliquely  across  the  perinseum, 
about  half  an  inch  in  front  of  the  anus.  It  arises  from  the  inner  surface 
of  the  hip-bone  in  front  of  the  ischial  tuberosity:  and  its  fibres  are  di- 
rected obliquely  forwards  to  the  central  point  of  the  perinseum,  where  it 
joins  the  muscle  of  the  opposite  side  and  the  external  sphincter.  "When 
the  muscle  is  largely  developed  it  unites  with  the  accelerator  urinae  by  a 
considerable  slip  (transversalis  alter).  Behind  this  muscle  the  superficial 
fascia  bends  down  to  the  triangular  ligament;  and  when  the  fascia  is  re- 
moved the  muscle  hangs  lower,  as  on  the  right  side  in  the  Plate. 

This  muscle  when  acting  with  its  fellow  fixes  and  draws  downwards 


MUSCLES    OF   THE    URETHKA    AND    PENIS.  19 

and  backwards  the  central  point  of  the  perinaeum:  the  two  may  compress 
slightly  tlic  bulb  of  the  urethra  beneath. 

The  cjnculator  uriiKB,  D,  covers  the  nrethra,  and  consists  of  two 
halves,  right  and  left,  which  are  united  by  a  tendon  in  the  middle  line. 
The  fibres  of  each  half  arise  from  the  median  tendon  and  frpm  the  cen- 
tral point;  and  they  are  directed  outwards  over  the  urethra  to  be  inserted 
by  three  slips  in  the  following  manner: — The  anterior  fasciculus,  formed, 
by  the  longest  fibres,  takes  its  attachment  to  the  outer  part  of  the  penis; 
the  posterior  is  inserted  into  the  subjacent  triangular  ligament;  and  the 
middle  or  intermediate  turns  round  the  urethi-a,  and  unites  with  the  cor- 
responding slijD  of  the  other  side.  The  muscle  covers  the  spongy  part  of 
the  urethra  for  about  two  inches  in  front  of  the  triangular  ligament;  and 
the  manner  in  which  the  tube  is  surrounded  will  appear  when  the  ejacu- 
lator  is  detached  in  a  deeper  dissection. 

By  surrounding  the  urethra  the  muscle  acts  as  a  sphincter  on  that  pas- 
sage, and  can  expel  with  force  the  fluid  from  the  tube.  During  the  con- 
tinuous flow  of  the  urine  the  fibres  of  both  sides  are  relaxed;  but  at  the 
time  of  the  expulsion  of  the  last  of  the  stream  they  come  into  forcible 
contraction  under  the  influence  of  the  will.  In  the  expulsion  of  the 
semen  the  action  of  the  muscle  is  involuntary. 

Erector  ijenis,  F.  This  muscle  conceals  the  crus  penis.  It  is  attach- 
ed to  the  innominate  bone  on  each  side  of,  and  behind  the  crus;  and  it  is 
inserted  anteriorly  by  aponeurotic  fibres  into  the  inner  and  outer  surfaces 
of  the  crus,  where  this  joins  the  body  of  the  penis. 

It  compresses  the  crus  penis  on  which  it  lies,  and  retards  the  escape 
of  blood  from  that  body  through  the  veins:  in  this  way  it  assists  in  the 
distention  of  the  j)enis. 

A  triangular  interval  exists  between  the  three  muscles  above  described. 
It  is  bounded  externally  by  the  erector  penis,  F,  internally  by  the  ejac- 
ulator  urin^e,  D,  and  posteriorly  by  the  transversalis  perinaei,  0.  In  the 
area  of  this  space  the  triangular  ligament  appears;  and  the  superficial 
perinaeal  vessels  and  nerves  course  forwards  through  it.  In  the  first  stage 
of  the  lateral  o|)eration  for  stone,  when  the  operator  is  making  a  way 
down  to  the  urethra,  the  knife  may  be  brought  into  the  hinder  part  of  the 
space,  and  may  cut  through  the  transverse  muscle,  part  of  the  ejaculator, 
and  some  of  the  superficial  perinaeal  vessels  and  nerves.  This  is  likely  to 
happen  if  the  cutaneous  incisions  are  begun  too  far  forwards;  but  if  the 
operation  is  well  planned  and  executed,  the  scalpel  will  be  sunk  behind 


20 


ILLUSTRATIONS    OF    DISSECTIONS. 


the  transversalis  muscle,  and  through  the  levator  ani  at  the  fore  and  inner 
part  of  the  ischio-rectal  fossa. 

8upe7]ficial perifimal  vessels.  The  arteries  which  are  distributed  to  the 
superficial  muscles  and  the  integuments  are  derived  from  the  pudic  trunk. 
Veins  accompany  the  arteries,  and  end  in  the  pudic. 


a.  Superficial  perinseal  artery. 
&.  Transverse  perinseal  artery. 


c.  Cutaneous    offsets    of  the  super- 
ficial perinseal  to  the  thigh. 


The  superficial  perincBal  artery,  a,  arises  from  the  pudic  trunk  near 
the  front  of  the  ischio-rectal  fossa,  and  crosses  over  the  transversalis  mus- 
cle as  it  courses  forwards  to  end  in  the  scrotum;  at  the  fore  part  of  the 
peringeum  it  divides  into  pieces,  and  it  is  sometimes  split  into  two  from 
the  origin.  It  furnishes  offsets  to  the  superficial  perinseal  muscles,  to 
the  integuments  of  the  thigh,  and  sometimes  the  following  branch. 

The  transverse  perinaal  artery,  h,  comes  either  from  the  preceding  or 
from  the  pudic  trunk  near  it,  and  passes  inwards  behind  the  transversalis 
to  end  in  the  integuments,  and  in  the  muscles  between  the  rectum  and 
the  urethra. 

The  veins  with  the  superficial  perinaeal  artery  are  large  and  plexiform 
at  the  scrotum. 

Superficial  perinceal  nerves.  Three  nerves  supply  the  integuments 
and  the  muscles;  and  these  are  offsets  of  the  pudic  and  small  sciatic. 


1.  Inferior  hsemorrhoidal  nervfe. 

2.  Posterior  of  the  two  superficial 

perinseal. 


3.  Anterior  of    the    two  superficial 

perinseal. 

4,  Inferior  pudendal  nerve. 


Two  superficial  perinmil  nerves  come  from  the  large  perinseal  branch 
of  the  pudic  in  the  ischio-rectal  fossa  (p.  14),  and  run  forwards  with  the 
vessels  to  the  scrotum,  in  which  they  ramify.  At  the  scrotum  they  unite 
together,  as  well  as  with  the  inferior  pudendal. 

The  more  posterior  branch,  2,  which  is  likewise  the  most  superficial, 
ends  chiefly  in  the  integuments.  The  anterior  nerve,  3,  passes  generally 
nnder  the  transversalis  muscle,  and  supplies  the  levator  ani  and  the  other 
superficial  muscles  as  it  is  directed  forwards  to  the  scrotum. 

The  inferior  pudendal  nerve,  4,  is  a  branch  of  the  small  sciatic,  and 
pierces  the  fascia  lata  of  the  thigh  near  the  border  of  the  gluteus  maxi- 
mus.     Thence  being  directed  forwards,  it  pierces  the  superficial  fascia, 


PLATE  XXXi 


if 


THE  URETHKA  AND  THE  TRIANGULAR  LIGAMENT.  21 

and  accompanies  the  otlier  nerves  to  tlie  scrotum.  Soon  after  it  appears 
it  is  joined  by  the  inferior  htemorrhoidal;  and  nearer  the  scrotum,  by  the 
superficial  perinaeal  branch. 

From  the  superficial  position  of  the  spongy  part  of  the  urethra,  a 
catheter  or  sound  passing  along  it  can  be  felt  readily  throughout;  and  in 
a  case  of  difficulty  in  moving  the  instrument  along,  assistance  may  be 
given  with  the  finger  of  the  other  hand. 

Stricture  of  the  urethra  is  most  frequent  where  the  tube  is  covered  by 
the  ejaculator  urin^e  muscle.  In  the  operation  of  cutting  down  upon  the 
stricture  from  without,  the  muscle  and  the  spongy  wall  of  the  urethra 
will  have  to  be  divided,  but  there  will  be  little  danger  of  bleeding  if  the 
incision  lies  directly  in  the  middle  line,  for  no  vessel  of  any  size  will  be 
met  with  in  that  position;  and  if  the  knife  is  passed  through  the  median 
tendinous  line  between  the  ejaculator  muscles,  the  only  structure  to  fur- 
nish blood  is  the  spongy  vascular  wall  of  the  urethra. 

If  openings  in  the  tube  of  the  urethra  should  occur  in  consequence  of 
disease  or  accident  the  urine  may  escape  from  the  passage,  and  become 
diffused  beneath  the  superficial  fascia  of  the  perinseun.  After  the  fluid 
is  extravasated  it  will  be  directed  forwards  to  the  scrotum,  as  before  said, 
by  reason  of  the  insertion  of  the  superficial  fascia  into  the  firm  under- 
lying parts  (p.  17). 


DESCRIPTION  OF  PLATE  XXXI. 


This  figure  is  designed  to  exhibit  the  triangular  ligament  of  the 
urethra,  and  the  muscles  and  vessels  inclosed  in  it. 

This  third  dissection  of  the  perinseum  may  be  made,  after  the  preced- 
ing, by  taking  the  ejaculator  urinae  from  the  urethra,  and  by  detaching 
on  the  left  side  the  erector  penis  and  the  crus  penis  from  the  bone. 
Next  a  vertical  cut  on  the  left  side  may  be  carried  through  the  fore  part 
of  the  triangular  ligament,  for  the  lower  two  thirds  of  the  depth,  to  show 
the  parts  between  the  layers. 


22  ILLUSTKATIONS    OF    DISSECTIONS. 


THE  URETHRA  AND  THE  TRIANGULAR  LIGAMENT. 

The  tube  for  the  conveyance  of  the  urine  curves  through  the  fore  part 
of  the  permaeal  space  from  the  bladder  to  the  end  of  the  penis,  and  pierces 
the  triangular  ligament.  It  is  divided  into  three  regional  parts,  as  before 
said  (p.  17).  In  Plate  XL.  the  form  and  length  of  these  divisions  are 
better  displayed. 

The  spongy  or  outer  portion,  about  six  inches  in  length,  receives  its 
name  from  being  surrounded  by  a  vascular  structure,  the  corpus  spon- 
giosum urethr^e.  Posteriorly  the  spongy  material  swells  out  into  the 
bulb,  C,  where  the  diameter  of  the  canal  is  also  enlarged;  and  in  front  it 
is  dilated  into  the  glans  penis,  with  a  corresponding  dilatation  inside. 
Usually  there  is  a  median  depression  in  the  bulb,  over  the  position  of  a 
partition  which  divides  the  corpus  spongiosum  into  a  right  and  a  left 
half.  The  swelling  of  the  bulb  is  united  to  the  front  of  the  triangular 
ligament  by  fibrous  Lissue;  and  it,  with  about  two  inches  of  the  urethra, 
is  covered  by  the  voluntary  ejaculator  urinse  muscle. 

The  membranous  part  of  the  tube,  the  shortest,  is  directed  upwards 
and  backwards  through  the  layers  of  the  triangular  ligament.  Its  length 
is  three-fourths  of  an  inch.  Its  distance  frem  the  symphysis  pubis  is  an 
inch,  and  it  lies  equidistantly  between  the  hip-bones.  Within  the  layers 
of  the  triangular  ligament  it  is  surrounded,  like  the  spongy  part,  with  a 
voluntary  muscle,  the  constrictor  urethrse,  H. 

The  prostatic  or  the  innermost  portion  of  the  urethra  is  about  one 
inch  and  a  quarter  in  length.  It  is  contained  altogether  in  the  pros- 
tate; and  it  will  have  the  same  connections  with  surrounding  parts  as 
that  body. 

The  triangular  ligament,  K,  acts  as  a  supporting  structure  to  the 
urethra,  and  fills  the  fore  part  of  the  pubic  arch:  it  closes  also  the  inter- 
val between  the  contiguous  borders  of  the  levatores  ani.  Its  widest  part  is 
turned  backwards;  and  its  length  is  one  inch  and  a  half  at  the  centre 
from  above  down. 

It  is  connected  with  the  parts  around  in  the  following  way: — The  apex 
is  united  with  the  symphysis  pubis.  The  base,  somewhat  arched  on  each 
side,  joins  in  the  middle  line  the  central  point  of  the  perinseum,  whilst 
laterally  it  is  connected  with  the  superficial  fascia,  and  with  a  fascia  cov- 


DEEP    MUSCLES    OF    THE    URETHRA.  23 

ering  the  levator  ani  in  the  ischio-rectal  fossa.  On  each  side  the  liga- 
ment is  fixed  into  the  hip-bone. 

Two  membranous  strata  enter  into  the  composition  of  the  triangular 
ligament:  they  are  named  anterior  and  posterior,  and  are  near  together 
above,  but  are  separated  below  by  the  urethra  and  its  muscles.  Only  tlie 
anterior  layer  is  visible  in  the  Plate. 

The  anterior  layer,  partly  cut  through  on  the  left  side,  is  a  thin 
fibrous  membrane,  which  permits  the  subjacent  muscular  fibres  and 
the  vessels  to  be  seen  through  it.  It  has  several  apertures: — Thus  per- 
forating the  ligament  in  the  middle  line,  one  inch  from  the  pubes  and 
the  sides  of  the  pubic  arch,  is  the  tube  of  the  urethra;  and  midway  be- 
tween the  former  opening  and  the  pubes  the  dorsal  vein  of  the  penis 
pierces  both  layers  of  the  ligament.  On  each  side,  near  the  apex,  the 
dorsal  artery  and  nerve  of  the  penis  issue  through  separate  holes  in  the 
anterior  layer. 

The  posterior  layer  of  the  ligament  is  continuous  with  the  pelvic 
fascia;  and  it  may  be  seen  in  Plate  xxxix.  of  the  pelvis. 

Between  the  layers  of  the  ligament  on  each  side  the  following  parts 
are  inclosed.  Near  the  base  of  the  ligament,  and  directed  transversely  to- 
wards the  urethra,  are  the  deep  transverse  muscle,  J,  the  constrictor 
urethrge,  H;  and  under  these,  near  the  middle  line  and  below  the  tube 
of  the  urethra,  lies  Cowper's  gland.  Along  the  side  of  the  ligament, 
where  it  is  fixed  to  the  bone,  the  pudic  artery  is  situate:  this  sends  in- 
wards near  the  base  of  the  ligament  a  transverse  branch  to  the  bulb. 
And  by  the  side  of  the  artery,  but  deeper  than  it,  and  contained  in  a 
separate  tube  of  fascia,  is  the  pudic  nerve. 

MUSCLES   OF  THE   MEMBRANOUS  PART  OF  THE  URETHRA. 

Between  the  layers  of  the  triangular  ligament  two  muscles  are  included, 
viz.,  deep  transverse,  and  the  constrictor  urethras.  The  other  muscles  in 
the  Drawing  have  been  already  noticed  in  the  description  of  the  two  fore- 
going Plates. 


A.  Sphincter  ani  externus. 

B.  Levator  ani. 

C.  Bulb  of  the  urethra. 

D.  Ejaculator  urinae,  cut. 

E.  Gluteus  maximus. 


F.  Erector  penis. 

G.  Crus  penis,  cut. 

H.  Constrictor  urethrae. 
J.  Deep  transverse  muscle. 
K.  Triangular  ligament  of  the  ure- 
thra. 


24  ILLUSTRATIONS    OF    DISSECTIONS. 

The  deep  transverse  muscle,  J,  is  a  narrow  fleshy  slip  which  lies  along 
the  base  of  the  triangular  ligament,  nearly  beneath  the  superficial  trans- 
verse muscle.  Externally  it  arises  from  the  pubic  arch;  and  internally  it 
joins  below  the  urethra  the  muscle  of  the  opposite  side,  and  is  fixed  into 
the  central  point  of  the  peringeum.  This  muscle  is  not  always  separate 
from  the  following. 

The  muscle  acts  like  the  superficial  transverse  in  fixing  the  central 
point  of  the  peringeum,  and  drawing  it  backwards  towards  the  rectum. 

Constrictor  urethrce,  H,  This  muscle  extends  transversely  from  the 
pubic  arch  to  the  urethra,  and  unites  on  that  tube  with  its  fellow.  The 
two  muscles  taken  together  resemble  the  sphincter  ani  externus  placed 
transversely. 

It  has  a  tendinous  origin  from  the  pubic  arch  and  from  the  posterior 
layer  of  the  triangular  ligament;  and  it  divides  near  the  urethra  into  two 
fleshy  strata  which  pass,  one  over,  and  the  other  under  that  tube,  to  join 
similar  parts  of  the  muscle  of  the  opposite  side.  These  fleshy  strata  reach 
the  whole  length  of  the  membranous  part  of  the  urethra,  surrounding  it, 
and  end  in  a  median  tendon  (more  or  less  complete)  both  above  and  be- 
low the  passage. 

When  the  muscles  of  both  sides  act  the  urethral  canal  will  be  dimin- 
ished like  the  end  of  the  rectum  by  the  external  sphincter.  During  the 
act  of  making  water  the  muscles  are  relaxed;  but  they  act  spasmodically, 
like  the  ejaculatores  urinae,  in  expelling  the  last  portion  of  that  fluid,  or 
the  semen.  The  muscle  resembles  the  ejaculator  urinse  in  acting  only 
with  its  fellow. 

Orbicularis  iireihrce* — Encircling  the  urethral  tube  within  the  fibres 
of  the  constrictor  is  a  thin  layer  of  circular  involuntary  muscular  fibres, 
which  is  continuous  behind  with  the  fibres  of  the  prostate. 


PUDIC  VESSELS. 

The  trunks  of  the  pudic  artery  and  nerve  are  delineated  on  the  left 
side;  and  the  distribution  of  the  deep  muscular  branches  is  shown  on 
the  other. 


*  I  have  so  designated  this  muscle  from  its  arrangement  and  action,  and  have 
described  it  in  the  xxxix.  Vol.  of  the  Roy.  Med.  Chir.  Trans,  for  1856,  p.  337. 


PUDIC    VESSELS.  25 


a.  Pudic  artery  in  the  ischio-rectal 

fossa. 

b.  Pudic   artery   in  the   triangular 

ligament. 

c.  Dorsal  artery  of  the  penis. 


d.  Superficial  perinaeal,  cut. 

e.  Deep  transverse  perinaeal  branch. 
/.  Branch  to  corpus  spongiosum  ure- 

tlirae. 
n.  Artery  of  the  bulb. 


The picdic  artery,  a,  courses  along  the  osinnominatum,  and  lies  partly 
in  the  ischio-rectal  fossa,  and  partly  in  the  triangular  ligament.  The 
artery,  I,  between  the  layers  of  the  ligament  is  more  or  less  covered  by 
the  fibres  of  the  constrictor  urethrae,  and  gives  a  considerable  branch  to 
the  bulb  of  the  urethra.  Near  the  pubes  it  perforates  the  fore  part  of  the 
ligament,  and  becomes  the  dorsal  artery  of  the  penis,  c. 

As  soon  as  the  artery  appears  through  the  ligament  it  furnishes  a 
small  branch  (art.  corporis  cavernosi)  to  the  crus  penis:  this  has  not  any 
letter  of  reference. 

The  branch  of  the  hulb,  n,  is  seen  to  run  transversely  through  the 
fibres  of  the  constrictor,  and  about  half  an  inch  from  the  base  of  the  liga- 
ment, to  be  distributed  in  the  corpus  spongiosum  urethrge:  it  supplies  an 
offset  to  Cowper's  gland.  Most  commonly  it  is  superficial  in  part  to  the 
constrictor  muscle. 

If  this  branch  springs  from  the  pudic  trunk  below  the  level  of  the 
ligament  it  will  cross  the  front  of  the  ischio-rectal  fossa  to  reach  its  des- 
tination, and  will  be  liable  to  injury  in  the  lateral  operation  for  stone. 

Deep  muscular  branches.  These  arise  by  a  common  offset  from  the 
pudic  trunk,  or  from  the  superficial  perinaeal  artery  they  are  indicated 
on  the  left  side. 

A  deep  transverse  perinaeal  branch,  e,  which  is  sometimes  united  with 
the  superficial  transverse,  ends  in  the  fore  part  of  the  sphincter  and  the 
levator  ani.  From  it  an  offset  is  directed  through  the  base  of  the  triangu- 
lar ligament  to  supply  the  constrictor  urethrae  and  the  corpus  spongiosum 
urethra. 

Pudic  veins.  Two  veins  course  with  the  pudic  artery  along  the  side 
of  the  perinaeal  region,  and  they  are  joined  by  veins  which  accompany 
the  branches  of  the  artery.  The  companion  vein  of  the  dorsal  artery  of 
the  penis  does  not  join  the  pudic  veins,  but  enters  the  pelvis  through  the 
triangular  ligament,  and  ends  in  the  vesico-prostatic  plexus. 


26  ILLUSTRATIONS    OF    DISSECTIONS. 


PUDIC  NERVE  AND  ITS  DEEP  BRANCHES. 

The  pudic  nerve  lies  in  part  in  the  ischio-rectal  fossa,  and  in  part  in 
the  triangular  ligament;  and  finally  perforating  the  fore  layer  of  the  liga- 
ment, like  the  artery,  becomes  the  dorsal  nerve  of  the  penis. 

In  the  ischio-rectal  fossa  the  nerve  is  deeper  than  the  artery:  here  it 
furnishes  a  large  perinseal  branch,  which  passes  forwards  on  the  opposite 
side  of  the  pudic  artery,  and  splits  into  the  two  superficial  perinaeal  nerves 
before  described  (p.  20). 

Between  the  layers  of  the  triangular  ligament  the  nerve  remains  still 
deeper  than  the  pudic  vessels,  and  lies  in  a  separate  sheath  of  fascia.  No 
offsets  are  supplied  from  this  last  part  of  the  nerve. 

The  deep  branches  come  from  the  deeper  of  the  two  superficial  peri- 
nseal nerves: — One,  4,  pierces  the  triangular  ligament,  and  ends  in  the 
constrictor  urethra  muscle,  H;  this  same  branch  supplies  in  this  body  the 
erector  penis,  F.  Another  branch,  5,  enters  the  corpus  spongiosum  ure- 
thra. 

The  most  direct  and  the  shortest  course  into  the  bladder  from  the 
perinaeum  is  through  the  central  point,  which  is  marked  thus  *;  and 
through  it  the  membranous  part  of  the  urethra  is  entered  in  both  the 
median,  and  the  bilateral  operation  for  stone. 

In  the  lateral  operation  for  stone  the  surgeon  enters  the  knife  obliquely 
into  the  membranous  part  of  the  urethra. 

In  the  first  stage  of  the  operation  the  incisions  down  to  the  urethra 
are  carried  by  the  side  of  the  rectum  and  through  the  ischio-rectal  fossa, 
as  before  related  (p.  15),  instead  of  through  the  central  point  of  the 
perinasum. 

The  second  stage  consists  in  opening  the  membranous  portion  of  the 
urethra;  and  the  Drawing  shows  what  parts  would  be  cut  through  as 
the  knife  is  placed  in  the  staff.  Thus  the  base  of  the  ligament,  the  deep 
transversalis,  and  the  constrictor  urethrae  muscle,  and  the  deep  nerves 
and  vessels  (seen  on  the  right  side)  would  be  in  part  divided.  The  artery 
'of  the  bulb  ought  not  to  be  cut,  and  unless  the  first  incisions  are  begun 
too  far  forwards  it  will  not  be  injured,  when  it  has  its  ordinary  arrange- 
ment; but  when  it  arises  behind  the  triangular  ligament,  and  crosses  the 


PLATE  XXXII 


SUPERFICIAL    STRATA,    VESSELS,    AND    GLANDS.  27 

fore  part  of  the  ischio-rectal  fossa  to  reach  the  bulb,  it  lies  immediately  be- 
fore the  scalpel,  and  cannot  be  avoided  by  care  and  knowledge  on  the  part 
of  the  surgeon. 

In  the  third  stage  of  the  operation  the  knife  is  carried  through  the 
membranous  and  prostatic  parts  of  the  urethra  into  the  bladder:  the 
direction  of  the  incision,  and  the  parts  to  be  cut  through  and  avoided, 
will  be  best  understood  when  the  side  view  of  the  pelvis  is  referred  to 
(Plate  xl). 

In  retention  of  urine  from  stricture  at  the  back  of  the  spongy  portion 
of  the  urethra,  the  distended  membranous  part  of  that  tube  projects  to- 
wards the  surface  of  the  middle  of  the  triangular  ligament,  near  the  base, 
and  can  be  readily  reached  through  the  central  point  of  the  perineeum. 


ILLUSTRATIONS  OF  THE  ABDOMEN. 


DESCRIPTION  OF  PLATE  XXXII. 


A  SURFACE  view  of  the  lower  part  of  the  tendon  of  the  external 
oblique  muscle,  with  the  superficial  fascia,  vessels,  and  nerves  of  the 
groin. 

The  skin  being  reflected  from  the  groin  by  a  triangular  flap,  as  indi- 
cated in  the  Drawing,  the  fatty  layer  containing  the  vessels  comes  into 
sight;  and  this  with  its  vessels  may  be  thrown  towards  the  thigh,  like  the 
skin,  after  it  has  been  examined.  Underneath  it  appears  a  thin  fibrous 
layer,  H,  which  may  be  detached  from  the  aponeurosis  of  the  subjacent 
muscle  as  far  as  the  thigh.  The  tendon  of  the  oblique  muscle  may  then 
be  cleaned  with  little  trouble.  . 


SUPERFICIAL  STRATA,  VESSELS,  AND  GLANDS. 

Between  the  skin  in  the  groin  and  the  subjacent  muscles  two  super- 
ficial layers  are  interposed.  One  is  in  contact  with  the  cutis,  and  con- 
tains the  fat;  the  other,  thin  and  membranous,  rests  on  the  tendon  of 
the  external  oblique  muscle. 


28 


ILLUSTRATIONS   OF   DISSECTIONS. 


The  more  subcutaneous  fatty  layer,  called  the  superficial  fascia,  varies 
in  thickness  here  as  elsewhere  with  the  obesity  of  the  body.  In  it  ramify 
superficial  vessels  from  the  femoral  artery,  with  veins;  and  as  the  stratum 
is  separated  from  the  subjacent  one  by  a  line  of  glands  at  the  top  of  the 
thigh,  it  can  be  easily  raised  and  thrown  downwards,  as  in  the  Figure. 

The  deeper  stratum,  H,  thin  and  translucent,  is  destitute  of  fat,  and 
is  known  as  the  aponeurosis  of  the  fascia  lata  (Scarpa),  or  the  deep  layer 
of  the  superficial  fascia.  Distinct  from  the  subcutaneous  layer  at  the 
top  of  the  thigh,  glands  and  vessels  intervening,  it  becomes  thinner  and 
less  separate  as  it  ascends  on  the  abdomen.  Wlien  followed  down  to  the 
limb  it  will  be  found  to  blend  with  the  fascia  lata,  G-,  a  little  below  the 
tendon  of  the  external  oblique  muscle. 

Cutaneous  vessels. — In  the  fatty  layer  are  contained  the  following 
small  arteries  and  veins. 


a.  Superficial  epigastric  artery. 

5.  Superficial  pudic  artery. 

c.  Superficial  circumflex  iliac  artery. 


d.  Superficial  pudic  vein. 
e,  f.  Superficial  epigastric  veins. 


The  three  small  arteries  above  mentioned  ramify  in  the  fat;  they  are 
the  first  branches  of  the  femoral  trunk,  and  communicate  with  offsets  of 
deeper  arteries  similarly  named.  As  their  names  express,  the  pudic 
branch,  h,  ends  in  the  pubes  and  the  integuments  of  the  penis;  the 
epigastric,  a,  in  the  teguments  of  the  lower  part  of  the  belly;  and  the 
circumflex  iliac,  c,  in  the  fat  of  the  outer  portion  of  the  thigh.  Many 
variations  occur  in  their  arrangement:  in  this  body  the  epigastric  was 
divided  into  branches,  and  the  circumflex  iliac  was  small. 

As  the  superficial  pudic  crosses  the  cord  it  may  be  cut  when  the  in- 
teguments are  divided  in  the  operation  for  inguinal  hernia.  Usually  the 
vessel  is  so  small  as  to  be  disregarded,  because  the  haemorrhage  soon 
ceases  after  its  section;  but  if  the  bleeding  is  troublesome  a  ligature 
ought  to  be  placed  on  the  end  nearest  the  femoral  trunk. 

Veins.  Superficial  veins  of  the  same  name  run  with  the  arteries,  and 
have  a  like  extent.  Single  or  double  as  they  lie  with  the  arteries,  they 
converge  below  to  the  internal  saphenous  vein  into  which  they  open. 

Inguinal  glands.  \\  Along  the  line  of  Poupart's  ligament  lies  a  chain 
of  superficial  inguinal  lymphatic  glands,  which  is  marked  as  above.— They 
are  situate  between  the  subcutaneous  fatty  layer  and  the  thin  aponeurosis 
of  the  fascia  lata,  H,  and  receive  lymphatics  from  the  contiguous  parts  of 


FIRST   MUSCULAR    LA.YER. 


29 


tlic  abdomen  and  outside  of  the  pelvis,  and  from  the  genital  organs;  and 
they  communicate  by  deeper  lymjihatics  with  glands  by  the  side  of  the 
large. bloodvessels. — Usually  they  are  about  three  or  four  in  number,  but 
this  varies  with  their  size. 


FIRST  MUSCULAR  LAYER. 

The  outer  muscle  of  the  groin  is  the  external  oblique,  which  receives 
its  name  from  the  direction  of  the  fibres,  and  the  situation  in  the  abdo- 
minal wall.  Fleshy  on  the  sides,  it  is  tendinous  or  aponeurotic  on  the 
front  and  below;  and  near  the  middle  line  the  aponeurosis  blends  with 
the  tendon  of  the  muscle  beneath. 


A.  Aponeurosis     of    the    external 

oblique  rauscle. 

B.  External  pillar  of  the  abdominal 

ring. 

C.  Internal  pillar  of  the  abdominal 

ring. 

D.  Poupart's  ligament. 

E.  Spermatic  cord. 


F.  Intercolumnar  fibres. 

G.  Fascia  lata. 

H.  Aponeurosis  of  the  fascia  lata. 

I.    Linea  alba. 

J.    Linea  semilunaris. 

K.  Iliac  crest  of  the  hip  bone. 

ft  Inguinal  glands.     * 


The  lower  part  of  the  aponeurosis  has  the  following  attachments. 
Along  the  middle  line  it  unites  with  its  fellow  in  the  linea  alba,  I,  reach- 
ing to  the  front  of  the  os  pubis.  Below,  it  is  fixed  at  the  outer  part  to 
the  iliac  crest,  K,  and  at  the  inner  part  to  the  sjaine  and  pectineal  line  of 
the  pubes  by  the  slip,  B:  and  between  these  two  bony  attachments  it  forms 
the  strong  rather  rounded  band  of  Poupart's  ligament,  D,  across  the 
thigh. 

The  aponeurosis  is  constructed  of  separate  threads  directed  downwards 
and  inwards  obliquely.  Near  the  top  of  the  thigh  its  fibres  are  thicker 
than  elsewhere;  and  a  little  above  and  external  to  the  pubes  they  are 
separated  for  a  short  space,  so  as  to  leave  an  interval — the  external  abdo- 
minal ring.  For  the  purpose  of  binding  together  the  longitudinal  fibres 
and  giving  strength  to  the  aponeurosis,  a  stratum  of  oblique  fibres  (inter- 
columnar) is  continued  over  the  sarface.  Here  and  there  are  small 
apertures  in  it  for  the  transmission  of  superficial  vessels  and  nerves. 

The  named  parts  of  the  aponeurosis  visible  in  the  Drawing  are,  the 
linea  alba,  linea  semilunaris,  Poupart's  ligament,  and  the  external  ab- 
dominal ring. 


30  ILLUSTRATIONS    OF    DISSECTIONS. 

The  linea  alia,  I,  is  a  strong  tendinous  band  along  the  midline  of  the 
belly,  which  reaches  from  the  pelvis  to  the  chest,  and  in  which  the 
aponeuroses  of  the  flat  muscles  of  opposite  sides  are  blended. 

Linea  semilunaris,  J.  This  is  a  yellowish  line,  somewhat  depressed 
even  before  the  integuments  are  removed,  which  is  directed  upwards  from 
the  tuberosity  of  the  pubes  to  the  tip  of  the  eighth  rib.  It  marks  the 
position  of  the  outer  edge  of  the  rectus  muscle,  and  is  rather  less  strong 
below. 

Pouparfs  ligament,  D,  is  the  thickened  lower  edge  of  the  aponeurosis 
across  the  top  of  the  thigh.  Externally  it  is  rounded,  and  is  attached  to 
the  front  of  the  iliac  crest;  internally  it  becomes  widened,  and  is  fixed 
into  the  spine  and  the  pectineal  line  of  the  hip-bone:  and  below  it  blends 
with  the  fascia  lata,  G.  This  band  is  curved  downwards  towards  the 
thigh  so  as  to  make  the  outer  third  oblique,  and  the  inner  two-thirds 
more  horizontal  in  direction.  Like  the  linea  alba,  it  serves  as  a  fixed 
]Doint  for  the  underlying  muscles  and  the  surrounding  fascia.  It  receives 
also  the  name  crural  arch;  and  in  Plate  xliv.  the  reason  of  this  name 
appears,  as  the  aponeurosis  is  shown  arching  over  muscles,  vessels,  and 
nerves  at  the  top  of  the  thigh. 

This  firm  band  can  be  felt  readily  through  the  integument,  and  marks 
the  limit  between  the  abdomen  and  the  thigh.  Even  the  nature  of  a 
hernial  tumor  may  be  decided  by  its  position  to  the  band;  for  if  the 
swelling  lies  above  the  ligament  it  forms  an  inguinal  hernia,  and  if  it 
projects  to  the  surface  below,  it  constitutes  a  femoral  hernia. 

The  external  abdominal  ring  or  the  opening  in  the  aponeurosis  of  the 
oblique  muscle,  transmits  the  testicle  in  the  fetus.  Triangular  in  form, 
with  the  apex  upwards  and  outwards,  it  is  placed  outside  the  pubes  and 
extends  considerably  above  that  point  of  bone. — It  measures  commonly 
about  one  inch  from  base  to  apex,  and  half  an  inch  across;  but  it  varies 
much  in  size  in  different  bodies,  and  is  smaller  in  the  female  than  the 
male.  The  pieces  of  the  aponeurosis  bounding  it  laterally  are  named  the 
pillars.  The  inner  pillar,  C,  flat  and  thin,  is  continued  to  the  front  of 
the  pubes;  and  the  outer,  B,  curved  around  th^  spermatic  cord  which 
rests  on  it,  is  fixed  to  the  spine  of  the  pubes,  and  joins  Pouparfs  ligament 
below.  In  this  opening  lies  the  cord  in  the  male,  and  the  round  or  sus- 
pensory ligament  of  the  uterus  in  the  female;  and  through  it  the  in- 
guinal hernia  is  protruded. 

Prom  its  margin  a  thin  fascia  is  prolonged  on  the  spermatic  cord  or 


EXTERNAL    ABDOMINAL    RING. 


31 


the  round  ligament,  wliich  is  called  intercolumnar  from  its  position;  and 
when  this  covers  a  hernia  it  is  named  the  spermatic  fascia.  In  a  large 
hernia  this  stratum  becomes  much  thickened. 

Variations  in  the  size  of  the  opening  will  affect  differently  a  hernia 
protruding  through  it.  If  the  aperture  is  small  its  sharp  edges  will  offer 
some  resistance  to  the  return  of  the  gut,  and  may  even  constrict  the 
intestinal  vessels;  whilst  if  it  is  larger  than  usual  no  impediment  will 
arise  from  its  then  comparatively  lax  margins.  After  a  hernia  has  existed 
for  a  time  the  opening  assumes  a  rounded  form,  and  from  this  circum- 
stance the  term  "  ring''  has  been  derived. 

The  sharpness  of  the  edges  and  the  capacity  of  the  external  abdominal 
ring  are  modified  by  the  position  of  the  limb  to  the  trunk.  When  the 
limb  is  extended,  as  in  standing,  Poupart's  ligament  is  drawn  down  by 
the  tightened  fascia  lata  of  the  thigh,  and  the  margins  of  the  opening  are 
rendered  tense,  whilst  the  interval  between  them  is  diminished.  But 
when  the  limb  is  placed  in  the  opposite  state,  viz.,  raised  and  rotated  m, 
Poupart's  ligament  rises,  becoming  lax;  and  the  sides  of  the  ring  being 
loose,  greater  capacity  can  be  more  readily  imparted  to  it.  In  an  at- 
tempt therefore  to  push  back  a  hernia  the  manipulator  should  see  that 
the  hip-joint  is  bent  and  rotated  in,  whilst  the  body  is  in  a  recumbent 
posture,  in  order  that  no  impediment  shall  arise  from  unrelaxed  fascise  or 
tendons. 

Over  this  opening  the  pad  of  a  trass  has  to  be  placed  in  internal  or 
direct  hernia;  and  its  position  on  the  surface  of  the  body  can  be  ascer- 
tained in  this  way: — Carry  the  forefinger  along  the  ridge  of  the  pubio 
crest  from  within  out,  and  as  soon  as  it  passes  the  limit  of  that  bony 
ridge  it  will  be  placed  over  the  external  abdominal  ring. 

The  intercolumnar  fibres,  F,  form  a  continuous  covering  upon  the 
aponeurosis  of  the  external  oblique.  Near  the  apex  of  the  abdominal 
ring  they  are  stronger  than  elsewhere,  and  to  the  thickened  band  in  that 
situation  the  name  ''intercolumnar"  is  given.  In  this  band  the  fibres 
form  arches  with  the  concavity  up,  and  are  prolonged  downwards  and 
outwards  to  Poupart's  ligament.  By  their  transverse  position  they  unite 
together  the  diverging  slender  threads  of  the  aponeurosis  of  the  oblique; 
and  passing  the  pillars  of  the  abdominal  ring  they  give  strength  to  that 
part  so  weakened  by  the  existence  of  a  large  hole. 

The  spermatic  cord,  E,  reaches  from  the  testicle  to  the  cavity  of  the 
abdomen,  and  passes  obliquely  through  the  grom  (Plate  xxxiv.).     It  con- 


32  ILLUSTRATIONS    OF    DISSECTIONS. 

sists  of  the  vessels,  nerves,  lymphatics,  and  excretory  duct  of  the  testicle, 
which  are  surrounded  by  covering  derived  from  the  abdominal  wall  and 
the  scrotum.  As  it  lies  in  the  external  abdominal  ring  it  rests  upon  the 
outer  pillar,  and  receives  the  thin  intercolumnar  covering  from  the  mar- 
gin of  that  opening.  A  hernia  escaping  through  the  external  ring  will 
be  superficial  to  the  cord,  and  will  descend  within  the  covering  derived 
from  the  margin. 

Cutaneous  vessels.  Several  small  arteries  with  companion  veins  issue 
through  apertures  in  the  aponeurosis  of  the  external  oblique;  these  are 
distinct  from  the  cutaneous  vessels  of  the  groin  before  described  (p.  28), 
which  belong  to  the  femoral  trunks. 

Five  small  arteries  appear  near  the  middle  line,  and  are  derived  from 
the  epigastric  in  the  abdominal  wall:  another  is  placed  near  the  iliac  crest 
of  the  hip-bone,  and  comes  from  the  circumflex  iliac  artery. — A  branch, 
larger  than  the  rest,  though  like  them  unnamed,  issues  through  the 
abdominal  ring  with  the  cord,  and  ends  in  the  integuments  of  the  scro- 
tum and  upper  and  inner  parts  of  the  thigh.  Cutaneous  nerves  ac- 
company most  of  the  arteries. 

Cutaneous  nerves.  The  nerves  are  more  constant  than  the  vessels  in 
their  position  and  distribution,  and  some  of  them  are  named:  they  perfo- 
rate the  aponeurosis  of  the  external  oblique. 


1.  Cutaneous  part  of  the  ilio-ingui- 

nal. 
3.  Ending  of  the  ilio-hypogastric. 


3.  Cutaneous  endings  of  the  dorsal 
nerves. 


The  ilio-inguinal  nerve,  1,  is  a  branch  of  the  lumbar  plexus.  It 
courses  through  the  parietes  of  the  abdomen  as  far  as  the  external  ab- 
dominal ring,  through  which  it  issues  to  supply  the  integuments  of  the 
scrotum  or  of  the  labium,  and  of  the  contiguous  part  of  the  thigh,  like 
its  companion  artery. 

The  ilio-hypogastric  nerve,  2,  arises  with  the  preceding  from  the 
lumbar  plexus,  and  passing  with  it  through  the  wall  of  the  abdomen,  ends 
near  the  pubes  m  the  integuments  of  the  hypogastric  region;  further  back 
it  gives  a  cutaneous  iliac  branch  over  the  crest  of  the  hip-bone. 

Dorsal  nerves.  The  lower  six  of  these  nerves  are  joartly  contained  in 
the  wall  of  the  abdomen:  they  perforate  the  external  oblique  tendon,  like 


PLATE  XXXI 


V 


-^^mi 


.^Y  "~*^'§«8B£^- 


\ 


\ 


\ 


\ 


SECOND    I-AYER    OF    THE    GROIN. 


33 


the  two  preceding,  and  ramify  in  the  teguments  near  the  middle  line  of 
the  body.  More  posteriorly  tliey  furnish  also  lateral  cutaneous  branches 
to  the  side  of  the  abdomen. 


DESCRIPTION  OF   PLATE  XXXIII. 


The  internal  oblique  muscle  with  the  cremascer  is  depicted  in  this 
Figure. 

This  dissection  of  the  second  layer  of  the  groin  will  be  completed  by 
cutting  through  and  reflecting  the  obliquus  externus  in  the  manner  shown, 
and  by  removing  from  the  fibres  of  the  internal  oblique  the  thin  inter- 
muscular layer  of  areolar  tissue. 

The  nerves  and  small  vessels  will  be  defined  as  the  areolar  tissue  is 
cleared  away. 


SECOND  LAYER  OF  THE  GROIN. 

Two  muscles  enter  into  the  second  stratum  of  the  groin:  of  these  the 
chief  one  is  the  internal  oblique,  and  to  it  the  cremaster  is  connected  be- 
low. 


A.  External  oblique  muscle. 

B.  Tendon  of  the  oblique  reflected. 

C.  Poupart's  ligament. 

D.  Cremaster  muscle. 


E.  Pyramidalis  muscle. 

F.  Spermatic  cord. 

G.  Internal  oblique  muscle. 
I.    Band  behind  Poup.  lig. 


Internal  oblique  muscle  G.  This  muscle  is  distinguished  from  the 
preceding  by  the  direction  of  its  fibres;  and  it  arches  over  the  spermatic 
cord,  instead  of  being  pierced  by  a  hole  for  the  same,  as  the  external 
oblique  is.  Below  it  possesses  fleshy  fibres,  where  the  obliquus  externus 
is  tendinous;  and  these  are  attached  (part  of  the  origin)  to  the  outer  half 
of  Poupart's  ligament,  C,  to  a  fibrous  band  behind  it,  I,  and  to  the  crest 
of  the  hip-bone.  From  this  origin  the  fibres  pass  forwards,  the  upper 
ascending,  and  the  lower  arching  over  the  spermatic  cord,  to  end  in  the 
common  tendon  or  aponeurosis. 

The  aponeurosis  of  the  muscle  unites  inseparably  with  that  of  the  ex- 


34  ILLUSTRATIONS    OF    DISSECTIONS. 

ternal  oblique  towards  the  middle  line  of  the  body,  and  ends  with  it  in 
the  linea  alba.  The  part  laid  bare  has  the  following  attachment  below: — 
it  is  inserted  into  the  front  of  the  pubes,  and,  farther  out,  into  the  pecti- 
neal line  for  half  an  inch.  Above  the  umbilicus  the  tendon  is  split  to 
incase  the  rectus  muscle,  but  midway  between  the  navel  and  the  pubes 
it  is  undivided,  and  is  continued  in  front  of  the  rectus. 

In  the  groin  the  muscle  covers  the  aperture  in  the  abdominal  wall 
through  which  the  testicle  escapes,  and  it  conceals  in  part  the  sjoermatic 
cord.  Its  lower  edge  is  free,  and  arches  over  the  cord:  contiguous  to  this 
edge  is  the  cremaster  muscle  D.  Several  superficial  nerves  and  vessels 
pierce  the  muscle. 

The  cremaster  muscle,  D,  .lies  along  the  lower  border  of  the  internal 
oblique;  and  covers  with  loops  the  spermatic  cord.  Externally  the  mus- 
cle arises  by  fleshy  fibres  from  Poupart's  ligament  below  the  internal 
oblique  and  transversalis,  some  fibres  blending  with  those  muscles;  and 
internally  it  is  inserted  by  tendon  into  the  pubes  and  the  aponeurosis  of 
the  internal  oblique.  It  has  the  following  arrangement  with  respect  to 
the  spermatic  cord: — On  each  side  it  forms  a  fleshy  bundle,  the  external 
being  the  strongest,  and  over  the  front  of  the  cord  it  gives  rise  to  a  series 
of  loops  which  reach  to  the  testicle.  Further  the  fleshy  loops  are  united 
by  areolar  tissue  so  as  to  produce  a  continuous  layer — the  cremasteric 
covering  of  the  cord:  this  layer  is  named  the  cremasteric  fascia  when  it 
forms  an  investment  for  an  inguinal  hernia. 

By  the  shortening  of  its  loops  this  muscle  can  raise  the  testicle  towards 
the  abdomen:  its  action  is  chiefly  under  the  control  of  the  will,  but  at 
times  is  involuntary. 

Nerves.  Three  nerves  run  forwards  in  the  groin  between  the  external 
and  internal  oblique  muscles :  two  are  offsets  of  the  lumbar  plexus,  and 
the  other  is  derived  from  the  last  dorsal  (intercostal)  nerve. 


1.  Ilio-hypogastric  nerve. 

2.  Ilio-inguinal  nerve. 

3.  Cremasteric  branch. 


4.  Branch  to  pyramidalis  muscle. 
5    Offset  of  a  dorsal  nerve. 


The  ilio-hypogasiric  nerve,  1,  is  derived  from  the  lumbar  plexus,  and 
has  been  traced  at  its  ending  in  the  integuments  (Plate  xxxii.  p.  32). 
In  this  Illustration  of  the  dissection  of  the  groin,  the  nerve  is  shown 
piercing  the  internal  oblique  muscle,  near  the  iliac  crest,  and  the  aponeu- 


PLATE  XXXiV 


/ 


^  "!>•.>. 


;*^' 


\ 


X      % 


\ 


\ 


\ 


\ 


THIRD    STRATUM    OF    THE    GROIN. 


35 


rosis  of  the  external  oblique,  near  the  abdominal  ring,  in  its  course  to  the 
surface  of  the  abdomen. 

The  ilio-inrjuinal  nerve,  2,  is  an  offset  with  the  preceding  from  the 
lumbar  j^lexus.  Having,  at  first,  a  similar  course  with  its  companion,  it 
tlien  passes  through  the  internal  oblique  somewhat  lower,  and  issues  from 
the  wall  of  the  abdomen  at  the  external  abdominal  ring,  to  reach  the 
scrotum  and  the  integuments  of  the  top  of  the  thigh.  It  furnishes  an 
offset,  3,  to  the  cremaster,  and  another,  4,  to  the  pyramidalis  muscle. 

Last  dorsal  nerve,  5,  runs  forward  between  the  oblique  muscles,  and 
perforating  the  aponeurosis  of  the  external  muscle  opposite  the  linea 
semilunaris,  ends  in  the  teguments. 

Cutaneous  oessels.  A  few  unnamed  cutaneous  arteries  with  veins 
perforate  the  abdominal  muscles:  the  chief  of  these  are  situate  near  the 
middle  line,  and  are  derived  from  the  epigastric  vessels. 


DESCRIPTION  OF  PLATE. XXXIV. 


A  VIEW  of  the  transversalis  muscle  and  fascia,  with  the  spermatic  cord, 
appears  in  the  Plate. 

Supposing  the  internal  oblique  laid  bare  as  in  the  preceding  Plate,  this 
dissection  will  be  made  ready  by  cutting  vertically  through  the  lower 
three  inches  of  the  muscle  near  Poupart's  ligament,  and  reflecting  it  in- 
wards.    The  cremaster  may  be  separated  afterwards  from  the  cord. 


THIED  STRATUM  OF  THE  GROIN. 

All  the  muscles  of  the  abdominal  wall  come  into  sight  in  this  Illus- 
tration, the  transversalis  being  the  deepest;  and  under  this  last  mus- 
cle lies  the  fascia  transversalis. 


A.  External  oblique  muscle. 

B.  Aponeurosis  of  external,  reflect- 

ed. 

C.  Internal  oblique  muscle. 

D.  Internal  oblique,  reflected. 

E.  Cremaster  muscle. 

F.  Transversalis  muscle. 


G.  Tendon  of  the  transversalis. 

H.  Conjoined  tendon. 

I.    Fascia  transversalis. 

J.  Infundibuliform  fascia. 

K.  Spermatic  cord. 

L.  Internal  abdominal  ring. 

N.  Edge  of  the  rectus  muscle. 


36  ILLUSTKATIONS    OF    DISSECTIONS. 

The  transversalis,  ¥,  is  the  third  flat  muscle  in  the  wall  of  the  belly; 
and  it  takes  its  name  from  the  direction  of  its  fibres.  Like  the  oblique 
muscles,  it  is  fleshy  externally  and  tendinous  internally.  Tliepart  of  the 
muscle  in  the  groin  arises  by  fleshy  fibi-es  from  the  outer  third  of  Poupart's 
ligament  and  the  adjacent  fibrous  band,  and  from  the  iliac  crest;  the 
fibres  are  directed  transversely  forwards  to  the  aponeurosis,  but  the  lowest 
are  curved  above  the  cord,  as  this  lies  in  the  abdominal  wall. 

The  aponeurosis  unites  inseparably  with  that  of  the  internal  oblique, 
and  reaches  with  it  the  linea  alba.  Below,  it  is  attached  to  the  front  of 
the  pubes  like  the  internal  oblique,  and  to  an  inch  of  the  ilio-pectineal 
line  beneath  the  tendon  of  the  internal  oblique,  some  fibres  blending  with 
the  subjacent  fascia.  Above  the  umbilicus  the  aponeurosis  lies  beneath 
the  rectus;  biit  about  midway  between  the  navel  and  the  pubes  it  is  placed 
over  the  muscle. 

Conjoined  tendon,  H.  Kear  the  joelvis  the  aponeuroses  of  the  internal 
oblique  and  transversalis  are  partly  united  at  their  insertion  into  the 
pectineal  line  of  the  pubes,  and  form  the  stratum  of  the  conjoinod  ten- 
don. But  the  two  do  not  contribute  to  its  formation  in  equal  2:)roportions, 
for  the  aponeurosis  of  the  oblique  is  about  half  an  inch,  whilst  that  of  the 
transversalis  is  an  inch  in  width. 

Fascia  iransver sails,  I.  Beneath  the  transversalis  is  spread  a  thin 
fibrous  membrane,  which  takes  its  name  from  being  in  contact  with  that 
muscle.  Where  the  muscle  is  deficient  below  the  membrane  is  strongest; 
and  in  it  is  an  aperture,  L,- — the  internal  abdominal  ring,  through  which 
comes  the  spermatic  cord.  From  the  margin  of  the  ring  a  tube  of 
membrane,  J,  is  prolonged  around  the  cord,  like  a  glove  on  the  finger, 
and  is  named  the  funnel-shaped  covering  of  the  cord,  or  the  infundibu- 
liform  fascia  of  the  inguinal  hernia.  Outside  and  below  the  ring  the 
fascia  is  thicker  and  stronger  than  on  the  inside  where  the  epigastric 
vessels  appear  through  it.  At  Poupart's  ligament  the  fascia  descend 
beneath  that  band  into  the  thigh,  and  forms  the  fore  part  of  the  sheath 
incasing  the  femoral  vessels. 

The  internal  aldominal  ring,  L,  is  oval  in  form,  measuring  most 
from  above  down,  and  is  placed  about  half  an  inch  above  Poupart's  liga- 
ment: on  the  surface  of  the  abdomen  it  corresponds  with  a  spot  midway 
between  the  symphysis  pubis  and  the  iliac  crest,  and  a  finger's  breadth 
above  the  ligament  of  Poupart.  It  is  bounded  above  by  the  arched  bor- 
der of  the  transversalis  muscle,  F;  beloAv  by  Poupart's  ligament;  and  in- 


THIKI)    STRATUM    OF    THE    GROIN.  37 

ternally  by  the  epigastric  vessels.  In  this  opening  lies  the  spermatic  cord, 
and  through  it  a  piece  of  intestine  is  protruded  in  an  external  inguinal 
hernia.  The  tenseness  of  the  margin  of  the  ring,  as  well  as  of  the  fascia 
in  which  it  is  situate,  is  determined  by  the  position  of  the  limb;  for  when 
the  thigh  is  raised  and  rotated  in,  all  the  strata  of  the  wall  of  the  belly 
arc  relaxed,  but  when  tlie  limb  is  extended,  as  in  standing,  those  parts 
are  put  on  the  stretch.  The  influence  of  the  position  of  the  limb  on  the 
condition  of  the  opening  should  be  kept  in  mind  when  an  attempt  has  to 
be  made  to  return  a  hernia  into  the  cavity  of  the  abdomen. 

Sulperitoncal  fat.  Underneath  the  transversal  is  fascia  is  a  layer  of 
fat,  varying  in  thickness  with  the  obesity  or  leanness  of  the  body,  which 
gives  a  covering  also  to  the  spermatic  cord.  (Tn  looking  into  an  open 
abdomen  this  layer  is  recognized  beneath  the  peritoneum;  and  from  this 
circumstance  the  name  has  been  obtained. 

Peritoneum.  Still  within  the  subperitoneal  fat  is  the  stratum  of  the 
serous  membrane  of  the  abdomen,  or  the  peritoneum.  This  is  a  thin 
translucent  layer,  not  now  visible,  from  which  an  offset  in  the  fetus  (pro- 
cessus vaginalis  peritonei)  was  continued  around  the  testicle  passing  from 
the  abdomen  to  the  scrotum:  of  this  prolongation  one  or  two  fibrous 
bands  can  be  usually  discovered  in  the  adult,  descending  in  front  of  the 
vessels  of  the  cord,  and  within  the  tube  of  the  fascia  transversalis. 

The  spermatic  cord,  K,  reaches  from  the  testicle  to  the  opening  of  the 
fascia  transversalis,  and  consists  of  the  vessels  connecting  that  viscus  with 
parts  in  the  abdomen.  In  the  groin  it  lies  obliquely  amongst  the  ab- 
dominal muscles  in  a  channel  called  the  inguinal  canal;  and  it  pre- 
disposes by  its  situation  to  the  escape  of  a  piece  of  intestine  from  the  ab- 
domen. Beyond  the  abdominal  wall  it  hangs  vertically  to  the  testicle, 
and  can  be  felt  on  the  surface  of  the  body. 

Roundish  in  form  and  about  half  an  inch  in  diameter,  it  is  composed 
of  the  vessels  and  the  efferent  duct  of  the  testicle,  with  nerves,  lymphatics, 
and  areolar  tissue.  It  is  surrounded  by  coverings  from  the  structures 
amongst  or  through  vvhich  it  passes,  which  come  in  the  following  order 
when  enumerated  from  without  in: — the  integuments,  including  the  skin, 
and  the  superficial  fascia  or  the  subcutaneous  fatty  layer;  the  spermatic 
fascia  (Plate  xxxii. ) :  the  cremasteric  covering  (Plate  xxxiii. ) ;  the  funnel- 
shaped  covering  (xxxiv.);  and  beneath  all  the  subperitoneal  fat.  In  the 
fetus  at  the  time  of  the  passage  of  the  testicle  there  was  an  additional 
partial  covering  of  the  peritoneum,  but  this  disappears  with  the  subse- 


38  ILLUSTRATIONS    OF    DISSECTIONS. 

qiient  change  taking  place  in  the  prolongation  from  that  membrane. 
These  several  investments  will  clothe  successively  a  piece  of  gut  protrud- 
ing along  the  cord. 

Deei^  vessels  of  the  groi7i.     Vessels  from  two  sources,  the  epigastric 
and  circumflex  iliac,  are  met  with  in  this  dissection. 


a.  Epigastric  artery  and  veins. 
6.  Branches  of  circumflex  iliac. 


c.  Cremasteric  branches   of  the  epi- 
gastric. 


The  epigastric  artery,  a,  is  derived  from  the  external  iliac,  and  as- 
cends obliquely  upwards  and  inwards  across  the  groin  to  enter  the  sheath 
of  the  rectus  muscle.  The  part  now  seen  lies  close  inside  the  internal 
abdominal  ring,  and  beneath  the  fascia  transversal  is. 

It  furnishes  small  branches  internally  and  externally:  two  of  the  outer 
set  marked  with,  c,  enter  the  cremaster,  and  receive  their  appellation 
from  that  muscle. 

The  circumflex  iliac  artery  arises  from  the  external  iliac  opposite  the 
epigastric  (Plate  xxxv.),  and  runs  beneath  the  transvcrsalis  muscle  round 
the  iliac  crest.     Offsets,  h,  are  given  to  the  contiguous  muscles. 

Veins.  Two  veins  belong  to  each  artery,  but  they  blend  into  one  in 
each  case,  and  end  in  the  external  iliac  near  Poupart's  ligament. 

ANATOMY  OF  INGUINAL  HERNIA. 

A  protrusion  of  intestine  through  the  wall  of  the  belly  in  the  groin 
constitutes  an  inguinal  hernia.  It  may  escape  through  the  internal  ab- 
dominal ring  with  the  cord;  or  it  may  be  placed  still  more  internally — 
opposite  the  conjoined  tendon,  H.  If  the  gut  descends  with  the  cord  it 
lies  outside  the  epigastric  artery,  and  the  hernia  is  called  external  in- 
guinal. But  if  the  intestine  makes  a  way  for  itself  opposite  the  conjoined 
tendon  the  tumor  forms  an  internal  inguinal  hernia  in  consequence  of  its 
position  inside  the  epigastric  vessels.  The  differences  between  these  two 
kinds  of  hernia  Avill  now  be  adverted  to. 

External  inguinal  hernia  is  directed  downwards  by  the  side  of  the 
spermatic  cord;  and  it  is  called  also  oblique  inguinal  hernia  from  its 
direction  in  the  abdominal  wall. 

Inguinal  canal.  The  channel  in  the  groin  along  which  the  intestine 
finds  its  way  is  the  inguinal  canal.     This  is  a  narrow  passage  between  the 


ANATOMY    OF    INGUINAL    HERNIA.  39 

muscles,  which  reaches  from  the  internal  to  the  external  abdominal  ring. 
Its  direction  is  oblique  downwards  and  inwards;  and  its  length  is  about 
one  inch  and  a  half.  It  is  constructed  by  the  strata  in  the  wall  of  the 
belly  in  this  manner: — Bounding  the  canal  superficially,  for  its  whole 
length,  are  the  teguments,  with  the  aponeurosis  of  the  external  oblique, 
B;  and  deeper  than  the  last  and  at  the  outer  end,  is  placed  the  fleshy 
part  of  the  internal  oblique,  D,  with  the  cremaster,  E,  along  its  border. 
Separating  the  passage  from  the  abdominal  cavity,  comes  first  the  con- 
joined tendon,  H,  for  a  short  distance  towards  the  inner  end;  and  behind 
it,  reaching  the  whole  length,  lie  the  fascia  transversalis  I,  the  subperi- 
toneal fat,  and  the  peritoneum. 

The  upper  opening  of  the  inguinal  canal,  by  which  the  gut  enters,  is 
the  internal  abdominal  ring  (p.  36);  and  the  lower  opening,  through 
which  the  intestine  escapes  from  the  wall  of  the  belly,  is  the  external 
abdominal  ring  (p.  30). 

Coverings. — A  piece  of  intestine  coming  outwards  through  the  inter- 
nal abdominal  ring,  L,  receives  investments  from  the  surrounding  strata. 
Some  of  these  exist  as  tubes  around  the  cord  ready  for  the  reception  of 
the  nascent  hernia,  whilst  others  originate  during  the  protrusion  of  the 
intestine.  As  the  intestine  is  forced  gradually  onwards  it  elongates  and 
forms  for  itself  coverings  of  the  peritoneum  and  the  subperitoneal  fatty 
layer.  And  it  is  then  received  into  the  following  tubes  around  the  cord, 
viz.,  the  prolongation  of  the  fascia  transversalis  (infundibuliform  fascia), 
the  fleshy  covering  of  the  cremaster  muscle  (cremasteric  fascia),  the  inter- 
columnar  layer  from  the  external  oblique  (spermatic  fascia),  and  lastly 
the  subcutaneous  fatty  layer  (superficial  fascia),  and  the  skin.  The  most 
internal  covering  of  the  intestine,  the  peritoneal  or  serous,  is  named  the 
sac  of  the  hernia.  If  the  gut  protrudes  through  the  wall  of  the  belly  it 
will  be  clothed  with  all  seven  of  the  coverings  enumerated  above,  and 
will  form  a  complete  hernia;  or  if  it  enters  the  scrotum  it  constitutes  a 
scrotal  rupture  (oscheocele).  But  if  the  intestine  is  stopped  in  its  course 
in  the  abdominal  wall  it  gives  rise  to  an  incomplete  hernia,  or  a  groin 
tumor  (bubonocele). 

Diagnosis. — In  distinguishing  the  external  or  oblique  from  the  in- 
ternal hernia  the  greatest  assistance  will  be  derived  from  the  direction 
and  form  of  the  tumor.  When  it  is  small,  and  is  still  confined  to  the 
abdominal  parietes,  its  recognition  will  be  insured  by  the  swelling  taking 
the  direction  of  the  inguinal  canal,  and  leading  to  the  internal  abdominal 


40  ILLUSTRATIONS    OF   DISSECTIONS. 

ring  where  the  neck  of  the  tumor  sinks  into  the  abdomen;  and  even  an 
aperture  may  be  recognized  with  the  tip  of  the  finger  when  the  intestine 
has  been  pushed  back.  After  the  rupture  has  passed  beyond  the  bounds 
of  the  abdominal  wall  the  swelling  becomes  flask-shaped  with  the  large 
end  towards  the  scrotum,  and  with  a  narrow  neck  running  upwards  and 
outwards  in  the  groin  to  the  position  of  the  internal  abdominal  ring. 
With  the  aid  of  the  fore  finger  the  hernia  may  be  ascertained  to  lie  in 
front  of  and  rather  to  the  outer  side  of  the  spermatic  cord;  but  this 
diagnostic  mark  is  not  so  easy  to  detect  as  the  oblique  position  in  the 
groin.  The  diagnosis  is  not  to  be  made,  however,  under  the  following 
circumstances: — When  the  hernia  is  large  and  of  long  standing  the  weight 
of  it  draws  inwards  the  movable  internal  abdominal  ring  into  a  line  with 
the  external  ring,  obliterating  by  that  movement  the  obliquity  of  the  in- 
guinal canal,  and  causing  the  external  hernia  to  have  a  straight  course, 
and  the  appearance  of  an  internal  hernia. 

Taxis. — The  success  of  attempts  to  replace  a  piece  of  intestine  in  the 
cavity  of  the  abdomen  will  depend  mainly  upon  the  manipulator  keeping 
in  remembrance  the  direction  of  the  inguinal  canal,  and  the  influence  of 
the  jDOsition  of  the  limb  upon  the  tightness  of  the  structures  in  the  groin. 
Before  the  taxis  is  employed  the  recumbent  posture  is  required,  and  the 
thigh  is  to  be  raised  and  rotated  in,  so  that  the  apertures  through  which 
the  gut  escapes,  and  all  the  strata  in  the  groin,  may  be  relaxed  as  much 
as  possible.  To  effect  the  reduction  the  operator  grasps  the  end  of  the 
tumor  with  one  hand,  using  gradual  and  uniform  pressure  over  the  sur- 
face, whilst  with  the  two  fore  fingers  of  the  other  hand  he  endeavors  to  di- 
rect upwards  through  the  narrowed  neck  of  the  tumor  in  the  groin  some  of 
the  accumulated  fluid  and  gaseous  contents  of  the  gut.  In  this  proceed- 
ing success  will  be  more  likely  to  attend  on  the  efforts  of  the  person  who 
iis  mindful  of  the  position  of  the  internal  abdominal  ring,  and  of  the 
obliquity  of  the  inguinal  canal,  than  on  the  attempts  of  him  who  may 
disregard,  or  may  not  be  acquainted  with  those  facts.  Gentle  and  gen- 
eral pressure  continued  perseveringly  will  be  always  more  effective  than 
force  applied  partially  and  only  for  a  short  time,  in  evacuating  the  con- 
tents of  the  intestine,  and  in  returning  the  gut  into  the  cavity  of  the 
belly. 

Position  of  a  Truss. — After  a  hernia  has  been  reduced  it  must  be  kept 
in  the  abdomen  by  a  truss.  In  the  external  inguinal  hernia  the  ]3ad  of 
the  truss  should  close  the  internal  abdominal  ring;  and  it  should  be  ap- 


EXTERNAL    ABDOMINAL    RING.  41 

plied  to  a  point  in  the  groin  half  an  inch  above  Poupart's  ligament,  and 
about  midway  bet-ween  the  pubes  and  the  front  of  the  iliac  crest.  In  the 
other  kind  of  inguinal  hernia  (internal)  the  pad  of  the  truss  will  occupy 
a  different  position  (p.  45). 

Stricture. — If  the  intestine  cannot  be  restored  to  its  natural  cavity  by 
the  taxis,  the  contents  of  the  alimentary  canal  accumulate  in  it;  and  the 
veins  in  the  wall  of  the  gut  being  compressed  by  the  edge  of  the  narrowed 
hole  of  one  of  the  abdominal  rings  (generally  the  internal)  are  incapable 
of  returning  their  contents,  so  that  swelling,  and  more  or  less  complete 
stagnation  of  the  flow  of  blood  ensue.  In  this  way  the  intestine  may  be 
strictured  or  strangulated,  according  to  the  degree  of  completeness  oi  the 
arrest  of  the  circulation.  The  constriction  may  be  placed  at  the  internal 
abdominal  ring;  at  the  external  ring;  or  more  rarely  at  the  lower  edge  of 
the  internal  oblique  muscle.  The  most  usual  site  of  stricture  is  at  the 
internal  abdominal  ring,  and  it  may  be  produced  in  two  ways: — either  it 
results  from  a  constricting  band  of  fibrous  tissue  outside  the  peritoneal 
sac;  or  from  a  thickening  of  the  peritoneum  itself  at  the  neck  of  the 
hernia,  so  as  to  form  a  sharp  firm  band  inside  the  sac,  by  which  the  arrest 
of  the  circulation  may  be  brought  about  when  the  faeces  accumulate  in 
the  intestine  and  increase  its  size  as  before  explained. 

Division  of  the  Stricture. — Division  of  the  band  impeding  the  return 
of  the  intestine  is  to  be  effected  by  the  operation  for  hernia.  The  seat  of 
stricture  cannot  be  ascertained  beforehand,  but  as  it  is  placed  most  fre- 
quently at  the  internal  abdominal  ring  the  incisions  are  planned  with  the 
view  of  laying  bare  the  neck  of  the  hernia;  and  as  there  are  two  kinds  of 
stricture — one  outside,  the  other  inside  the  sac  of  the  hernia,  the  mode 
of  proceeding  will  vary  with  each.  All  fibrous  bands  outside  the  neck  of 
the  sac  are  first  divided  in  an  operation,  and  an  endeavor  is  to  be  then 
made  to  push  back  gently  the  intestine  into  the  abdomen;  but  if  the  gut 
cannot  be  passed  through  the  narrowed  aperture  with  the  employment  of 
moderate  force,  the  peritoneal  sac  is  to  be  opened  below  the  neck,  and 
the  constricting  band  is  to  be  cut  from  within  out  on  a  director  intro- 
duced beneath  it  in  a  longitudinal  direction. 

Should  the  operator  ascertain  that  the  stricture  is  not  situate  at  the 
internal  abdominal  ring,  he  must  seek  it  lower  down  at  the  border  of 
the  internal  oblique,  or  at  the  external  abdominal  ring,  as  before  said. 
Supposing  the  constriction  to  be  present  at  one  of  those  spots,  an 
attempt  should  be  made  in  the  first  instance  to  relieve  the  intestine 


4:2  ILLUSTRATIONS    OF    DISSECTIONS. 

after  the  manner  above  explained,  and  without  opening  the  peritoneal 

sac. 

Varieties  of  external  herjiia. — Differences  in  the  state  of  the  perito 
neal  covering  or  sac  of  this  hernia  give  origin  to  two  varieties.  Usually 
these  occur  in  the  male  infant,  and  child;  but  they  maybe  present  in  the 
adult  male  if  the  peritoneum  has  the  same  arrangement  as  in  infancy,  in 
consequence  of  an  arrest  in  the  changes  commonly  ensuing  on  the  pas- 
sage of  the  testicle.  One  of  the  two  varieties  is  called  congenital  and  the 
other  infantile  hernia. 

Congenital  inguinal  hernia  differs  from  the  ordinary  external  hernia 
in  not  protruding  as  a  covering  for  itself  a  piece  of  peritoneum  to  form 
the  sac.  In  this  kind  the  intestine  descends  in  the  unclosed  peritoneal 
pouch  (processus  vaginalis  peritonei)  which  accompanied  the  testicle  at 
the  time  of  passage  from  the  abdomen  to  the  scrotum;  and  consequently 
it  touches  the  testicle,  reaching  downwards  in  front  of,  and  below  that 
viscus. 

Its  coverings  are  similar  to  those  of  an  ordinary  external  hernia,  but 
its  peritoneal  covering  or  the  sac  is  obtained  in  a  different  way  as  just  said. 

Congenital  hernia  would  be  recognized  both  in  the  infant  and  the 
adult  by  the  extent  of  the  descent  of  the  intestine,  for  this  reaches  as  far 
as  the  lower  end  of  the  testicle  or  beyond  it;  whilst  in  the  common  exter- 
nal hernia  the  tumor  is  stopped  on  a  level  with  the  top  of  the  testicle  as 
it  extends  into  the  scrotum. 

What  has  been  before  detailed  respecting  the  taxis  and  the  application 
of  a  truss,  the  seat  and  the  division  of  the  stricture  in  external  inguinal 
hernia,  will  apply  to  this  and  the  following  variety  of  the  same  kind  of 
rupture. 

Infantile  her^iia  is  due  like  the  congenital  to  an  unobliterated  state  of 
the  processus  vaginalis  peritonei  of  the  testicle;  and  it  received  its  name 
from  being  first  recognized  in  children.  The  state  of  the  peritoneum 
necessary  for  the  formation  of  this  hernia  is  the  following: — Commonly 
the  vaginal  pouch  of  peritoneum  of  the  testis  is  obliterated  in  the  fetus 
from  the  internal  abdominal  ring  down  to  the  testicle;  but  sometimes  it 
is  obliterated  only  for  a  very  short  distance  from  that  opening,  so  as  to 
leave  a  larger  sac  than  usual  around  the  testis,  which  reaches  upwards 
along  the  spermatic  cord  and  the  inguinal  canal.  This  developmental 
deviation  remains  permanently,  and  will  give  rise  at  any  period  of  life  to 
the  hernia  called  infantile. 


INTERNAL    INGUINAL    HERNIA.  43 

With  the  presence  of  the  state  of  the  peritoneum  above  described, 
should  an  external  hernia  take  place,  it  Avould  push  before  it  in  the  usual 
way  a  sac  of  the  peritoneum  with  the  subperitoneal  fat;  then  it  would  pass 
through  the  internal  abdominal  ring,  and  bo  received  into  the  tubes  or 
coverings  incasing  the  spermatic  cord  (p.  39).  But  as  it  makes  its  way 
along  the  inguinal  canal  and  the  cord  it  comes  to  be  placed  behind  the 
loose  unclosed  pouch  of  the  peritoneum  already  referred  to.  In  reality 
there  would  be  two  separate  serous  sacs  in  connection  Avith  this  kind  of 
hernia; — an  anterior  consisting  of  the  tunica  vaginalis  testis  which  would 
contain  only  serum.;  and  a  posterior,  the  sac  of  the  hernia,  opening  into  the 
cavity  of  the  belly,  in  which  the  intestine  is  lodged. 

Though  this  rupture  may  be  found  in  the  adult  as  well  as  in  the  child, 
like  the  congenital  kind,  there  is  not  any  sign  by  which  it  can  be  distin- 
tinguished  during  life  from  the  common  external  hernia. 

Evidence  of  the  existence  of  an  infantile  hernia  is  first  obtained  in  an 
operation  for  the  relief  of  the  strangulation.  Then,  as  the  knife  is  moved 
onwards  to  divide  the  stricture  it  opens  the  loose  sac  of  the  tunica  vagi- 
nalis, in  which  a  serous  fluid  is  generally  collected.  Should  the  stricture 
be  placed  inside  the  neck  of  such  a  hernia  the  hinder  second  sac  would 
have  to  be  cut  into  before  the  intestine  would  be  laid  bare. 

Internal  inguinal  liernia  comes  through  the  abominal  wall  at  a  spot 
internal  to  the  epigastric  artery,  and  obtains  its  name  from  its  position 
inside  that  vessel.  It  takes  a  straight  course  through  the  parietes  of  the 
abdomen  opposite,  H;  and  it  is  jiamedalso  direct  hernia  from  its  straight- 
ness  in  comparison  with  an  external  hernia.  '  • 

The  terms  complete  and  incomplete,  bubonocele  and  oscheocele  (p. 
39),  may  be  applied  to  this  as  well  as  to  the  external  hernia. 

Triangular  space  of  the  groin. — Inside  the  epigastric  vessels  is  the 
triangular  space  of  Hesselbach,  in  which  the  internal  rupture  comes  forth. 
It  is  bounded  externally- by  the  vessels,  a;  internally  by  the  edge  of  the 
rectus  muscle,  N;  and  below  by  Poupart's  ligament.  In  width  it 
measures  about  one  inch  and  a  half  at  the  base,  and  from  base  to  apex 
about  two  inches. 

The  following  is  the  arrangement  of  the  strata  within  the  space  above 
defined.  Firstly  come  the  teguments,  consisting  of  the  skin,  and  the  sub- 
cutaneous fatty  layer  or  the  superficial  fascia.  Beneath  the  teguments 
the  aponeurosis  of  the  external  oblique,  B,  covers  all  the  triangular  space. 


44:  ILLUSTRATIONS    OF    DISSECTIONS. 

and  is  pierced  by  the  large  external  abdominal  ring.  When  this  has  been 
reflected  the  sj)ermatic  cord,  clothed  by  the  cremaster  muscle,  E,  is  seen 
to  lie  along  tlie  base  of  the  space.  Still  deeper  is  the  conjoined  tendon, 
H,  which  is  formed  by  the  union  of  the  aponeurosis  of  the  internal  oblique, 
D,  and  transversalis,  F  (p.  36):  this  aponeurotic  layer  is  not  wide  enough 
to  cover  the  whole  of  the  space  included  between  the  edge  of  the  rectus 
and  the  epigastric  vessels,  therefore  there  is  an  interval  (about  half  an 
inch  wide)  between  its  outer  border  and  the  epigastric  vessels,  in  whicli 
the  next  stratum  appears.  Under  the  muscles  the  transversalis  fascia,  I, 
thesubjjeritonealfat,  and  the  peritoneum,  are  stretched  continuously  over 
the  area  of  the  space,  and  without  apertures  in  them. 

Coverings.  Tlie  position  of  the  hernia  in  the  triangular  interval  is  de- 
termined by  the  existence  of  a  pit  or  fossa  on  the  inside  of  the  abdominal 
wall  opposite,  H  (Plate  xxxv.);  and  it  is  at  this  jooint,  behind  the  con- 
joined tendon,  where  the  hernia  is  most  commonly  found.  As  the  exter- 
nal oblique  is  the  only  layer  with  an  aperture  in  it,  and  with  a  tube 
descending  from  its  margin,  all  the  coverings  of  the  rupture,  except  that 
one,  will  be  formed  anew,  being  elongated  from  the  several  strata  as  the 
intestine  gradually  makes  its  way  onwards.  The  intestine  in  advancing 
extends  firstly  the  peritoneum  and  the  subperitoneal  fat,  forming  the  sac 
out  of  the  former  of  the  two.  Then  it  pushes  forwards  the  fascia  trans- 
versalis, and  obtains  for  itself  another  thin  covering.  Nextly,  meeting 
with  the  obstructing  conjoined  tendon,  it  elongates  the  same;  or,  if  the  her- 
nia is  produced  suddenly,  the  tendon  may  be  slit  to  give  passage  to  the 
tumor.  Still  advancing,  the  rupture  passes  over  the  cord  and  the  cre- 
master muscle,  and  escapes  through  the  external  abdominal  ring,  where  it 
receives  the  investment  of  the  spermatic  fascia.  And  lastly  it  comes  to  be 
placed  under  the  superficial  fascia  and  the  skin,  as  it  descends  along  the 
sjoermatic  cord. 

Diagnosis.  As  this  hernia  enters  the  wall  of  the  belly  nearer  the  mid 
line  than  the  internal  abdominal  ring,  and  takes  withal  a  straight  course, 
it  comes  to  lie  rather  inside  the  spermatic  cord  as  it  escapes  through  the 
external  abdominal  ring,  and  rather  over  the  pubic  crest.  But  the  best 
diagnostic  marks  between  this  and  an  external  hernia  are,  the  straightness 
and  shortness  of  its  passage  through  the  abdominal  parietes,  and  the 
absence  from  the  inguinal  canal  of  a  narrowed  oblique  neck.  An  internal 
hernia  cannot  be  distinguished  from  an  external  when  the  last  is  large, 
and  has  been  of  long  standing  (p.  40). 


INTEBNAL   INGUINAL   HERNIA.  45 

Taxis.  When  the  rupture  has  to  be  reduced  success  will  be  greatly 
dependent  upon  a  correct  diagnosis  of  its  kind,  because  the  spot  at  which 
the  internal  hernia  leaves  the  abdominal  cavity  is  different  from  that  for 
the  external;  and  attempts  to  put  it  back,  which  would  be  useful  when 
the  kind  of  hernia  is  recognized,  might  be  injurious  when  this  has  been 
mistaken.  In  the  case  of  an  internal  hernia  the  passage  along  which  the 
fseces  have  to  be  directed  is  quite  straight  through  the  abdominal  wall, 
and  in  the  direction  of  a  line  carried  inwards  through  the  external  ab- 
dominal ring.  When  the  taxis  is  about  to  be  used,  the  first  requisite  is 
to  have  the  structures  in  the  groin  relaxed  by  placing  the  trunk  in  the  re- 
cumbent posture,  and  by  raising  the  thigh  and  rotating  it  inwards.  And 
during  the  employment  of  the  taxis  the  fundus  of  the  tumor  should  be 
compressed  evenly  and  steadily  with  the  grasp  of  the  one  hand,  whilst 
the  fore  fingers  of  the  other  are  used  to  direct  upwards  some  of  the  con- 
tents of  the  intestine. 

Position  of  the  Truss. — In  applying  a  truss  for  an  internal  hernia  the 
pad  of  the  instrument  is  to  be  placed  on  the  hole  in  the  aponeurosis  of 
the  external  oblique  muscle,  because  the  aperture  of  entrance  into  the 
wall  is  opposite  the  aperture  of  exit  from  the  same.  This  opening,  or 
the  external  abdominal  ring,  will  be  opposite  a  spot  on  the  surface  of  the 
body  immediately  outside  the  pubic  crest. 

Seat  of  Stricture.  The  band  constricting  the  intestine  may  be  found 
at  two  places.  Firstly  it  may  exist  at  the  narrowed  mouth  of  the  sac, 
and  may  be  produced  by  fibrous  tissue  external  to  that  part,  or  by  a 
thickening  of  the  wall  of  the  sac  inside  the  neck.  Secondly  it  may  result 
from  the  firm  sharp  margin  of  the  external  abdominal  ring. 

Division  of  the  Stricture.  Partial  or  complete  arrest  of  the  circulation 
in  the  intestine  follows  inability  to  reduce  the  rupture  by  the  taxis;  and 
an  operation  is  needed  to  set  free  the  gut  from  its  imprisonment;  and  to 
arrest  its  mortification.  An  incision  is  to  be  made  through  the  wall  of 
the  belly  down  to  the  neck  of  the  tumor,  to  remove  stricture  external  to 
the  sac;  but  should  this  proceeding  fail  in  its  object,  and  the  existence 
of  stricture  inside  the  neck  of  the  sac  be  made  thereby  probable,  the  peri- 
toneal covering  should  be  opened,  and  the  constricting  band  should  be 
divided  directly  upwards  by  means  of  a  knife  carried  along  a  director  in- 
serted under  it. 

As  a  large  apparently  internal  hernia,  with  a  straight  direction  through 
the  abdominal  wall,  may  have  begun  as  an  external  or  oblique  one,  and 


46  ILLUSTKATIONS    OF    DISSECTIONS. 

may  have  assumed  afterwards  the  look  of  an  internal  rupture  by  reason 
of  its  weight  (p.  40),  the  scalpel  should  be  kept  on  the  front  of  the  tumoi 
in  an  operation,  and  parallel  to  the  middle  line  of  the  body.  And  in 
dividing  the  stricture  the  cut  should  be  made  directly  upwards  in  the 
same  direction.  By  taking  these  precautions  the  danger  of  wounding 
the  epigastric  vessels  curving  around  the  neck  of  such  a  hernia  on  the 
inner  side  will  be  best  avoided. 

Variety  of  infernal  liernia. — Within  the  triangular  space  of  Hesselbach 
a  rupture  may  protrude  at  a  different  spot  from  that  above  mentioned. 
External  in  position  to  the  other,  it  will  be  placed  nearer  the  epigastric 
vessels,  a,  coming  out  between  them  and  the  edge  of  the  conjoined  ten- 
don, H.  Without  any  aperture  for  its  exit,  it  has  to  elongate  and  make 
coverings  for  itself,  like  the  common  form  of  internal  hernia  which  lies 
nearer  the  pubes. 

Course  and  coverings.  The  Drawing  demonstrates  the  oblique  course 
the  intestine  would  take  through  nearly  the  Avhole  of  the  inguinal  canal. 
As  the  rupture  is  placed  farther  out  in  the  triangular  space  than  the  con- 
joined tendon  it  will  want  necessarily  a  covering  from  that  stratum;  and 
it  differs  from  the  more  common  internal  hernia  in  not  possessing  that 
investment.  But  as  the  intestine  proceeds  along  the  inguinal  canal  and 
the  cord  it  slips  within  the  cremaster  muscle,  and  then  issues  from  the 
abdominal  wall  by  the  external  abdominal  ring,  forming  a  pear-shaped 
swelling. 

Its  coverings  from  within  out  will  be,  peritoneum  or  sac,  subperitoneal 
fat,  fascia  transversalis,  cremasteric  fascia,  spermatic  fascia,  and  the 
teguments  and  skm:  in  short,  they  are  the  same  as  to  number  and  struc- 
tures as  the  coverings  of  the  external  or  oblique  hernia. 

Diagnosis. — During  life  this  kind  of  the  internal  hernia  is  not  to  be 
distinguished  from  the  external  or  oblique  in  consequence  of  its  traversing 
so  much  of  the  inguinal  canal,  and  having  a  pear-shaped  form  like  that 
rupture. 

Taxis  and  the  truss.— From  an  inability  to  distinguish  this  tumor 
from  an  external  hernia,  which  it  would  resemble,  the  same  precautions 
for  insuring  the  return  of  the  intestine  by  the  taxis  are  to  be  taken,  as 
were  described  for  that  rupture  (p.  40).  And  the  pad  of  the  truss, 
which  is  to  keep  the  gut  in  its  cavity,  should  be  placed  near  the  situation 
of  the  internal  abdominal  ring,  or  where  an  aperture  can  be  recognized 
by  the  tip  of  the  fore  finger. 


PLATE  XXXV 


MM"- 


VARIETY    OF    INTERNAL   HERNIA.  47 

Seat  of  stricture.  The  remarks  before  made  on  tlie  cavise  and  situa- 
tion of  the  stricture  of  an  external  liernia  will  serve  for  this  rarer  kind  of 
internal  hernia  (p.  41). 

Division  of  the  stricture.  With  a  suspicion  of  the  existence  of  the 
kind  of  rupture  now  under  consideration  care  is  needful  in  cutting  down 
to  free  it  from  stricture;  for  the  epigastric  vessels  lie  on  the  outer  side, 
whilst  in  the  external  hernia,  from  which  it  cannot  be  disting-uished,  they 
are  placed  on  the  inner  side  of  the  neck  of  the  rupture.  In  cutting  down 
on  the  upper  part  of  the  hernia  to  divide  the  external  stricture  the  scalpel 
should  be  kept  well  on  the  front  and  midpart  of  the  tumor,  so  as  to  avoid 
the  vessels  lying  on  its  side,  after  the  manner  recommended  in  the  opera- 
tion on  the  large  doubtful  direct  liernia  (f>.,45h  cU^  in  dividing  the 
internal  stricture  of  the  neck,  after  opening  the  sac,  "tlie  cut  should  be 
made  directly  upwards  in  front-^,  and  opposite  J^  Saddle  of  the  hernia. 
Should  these  difSotMB^e,  observed  there  will  be  little  risk  of  iniurinff 
the  bloodvessels,  even  tflougli  the  di'agnb'sJ'^  •oeiwsfei  €ke  tW  Mnds  of 
hernia  cannot  be  established.      ^.:  ^  -      '[ '\t\    T^'r  > 


DESCRIPTION  OF  PLATE  XXXY. 


INNER  view  of  the  groin  with  the  apertures  through  which  the  intes- 
tine leaves  the  cavity  of  the  abdomen  in  hernia. 

To  prepare  the  dissection  throw  down  the  wall  of  the  abdomen  in  the 
left  groin  in  the  form  of  a  triangular  flap;  detach  the  peritoneum  and 
the  subperitoneal  fat  from  that  flap,  and  the  colon  from  the  iliac  fossa. 
On  the  removal  of  the  fat  and  areolar  tissue,  and  some  glands  from  the 
side  of  the  large  iliac  artery  and  vein,  the  different  smaller  vessels  and 
nerves  will  come  into  sight. 

By  separating  the  peritoneum  from  the  wall  of  the  pelvis  the  urinary 
bladder  and  the  obturator  vessels  appear;  but  in  the  dissection  here  de- 
lineated the  obliterated  hypogastric  artery  was  removed  from  the  bladder. 


i8 


ILLUSTRATIONS    OF    DISSECTIOJNS. 


INNER  STRATA  OF  THE  ABDOMINAL  WALL. 

Inside  the  muscles  of  the  abdominal  wall  in  the  groin  are  spread  some 
thin  membranes,  which  are  connected  with  hernia,  forming  coverings  for 
it.  In  the  inner  as  in  the  outer  view  the  firm  band  of  Poupart's  ligament 
appears. 


A.  Rectus    abdominis    under     the 

fascia. 

B.  Crural  arch. 

C.  Girabernat's  ligament, 

D.  Iliac  fascia. 

E.  Sigmoid  flexure  of  the  colon. 

F.  Internal  abdominal  ring. 

G.  Crural  ring. 


H.  Pectiueus    muscle     covered    by 

fascia  lata. 
I.  Inner  inguinal  fossa. 
J.  Urachus  of  the  bladder. 
K.  Vas  deferens  of  the  testis, 
L.  Fascia  transversalis. 
N.  Urinary  bladder. 


Peritoneum  and  subperitoneal  fat.  These  two  layers  have  been  neces- 
sarily detached  in  the  dissection:  they  cover  all  the  parts  now  laid  bare, 
separating  them  from  the  viscera,  and  they  close  the  apertures  of  the  in- 
ternal abdominal  and  the  crural  ring. 

The  crural  arcli,  B,  or  Poupart's  ligament  (p.  30),  stretches  across 
the  front  of  the  hip-bone,  arching  over  the  muscles,  vessels,  and  nerves, 
which  are  continued  from  the  cavity  of  the  abdomen  to  the  thigh. 
Rounded  externally  where  it  is  joined  to  the  hip-bone  and  is  united  with 
the  subjacent  parts,  it  is  separated  internally  by  the  iliac  vessels  from  the 
underlying  muscles  and  bone,  and  is  fixed  by  a  widened  part  (Gimbernat's 
ligament)  into  the  tuberosity  and  the  pectineal  line  of  the  pubes. 

Gimhernafs  ligament,  C,  is  that  part  of  the  Avidened  inner  attachment 
of  the  crural  arch,  which  intervenes  between  the  rounded  anterior  part,  B, 
and  the  bone  beneath.  Triangular  in  shape,  the  apex  is  inserted  into  the 
tuberosity  of  the  pubes,  and  the  base  is  turned  to  the  iliac  vein,  5.  From 
apex  to  base  it  measures  about  an  inch,  and  it  is  kept  on  the  stretch  by 
its  union  at  the  base  with  the  fascia  lata. 

The  fascia  transversalis,  L,  lines  the  wall  of  the  abdomen  as  low  as 
Poupart's  ligament.  Ceasing  opposite  that  band,  it  has  a  different  dis 
position  at  the  outer  and  inner  ends.  As  far  inward  as  the  letter  B,  it  is 
connected  to  the  ligament,  and  blends  with  the  iliac  fascia,  D:  between 


INNER    STRATA    OF    THE    ABDOMINAL    WALL.  49 

the  spot  referred  to  and  Gimbernat's  ligament  it  is  continued  beneath 
the  inner  half  of  llio  crural  arch,  and  enters  the  fore  part  of  the  loose  cru- 
ral sheath  around  the  femoral  vessel;  and  still  more  internally  it  is  fixed 
into  the  pectineal  line  of  the  pubes  beneath  the  conjoined  tendon  (p.  36) 
and  Gimbernat's  ligament.  Just  above  Gimbernat's  ligament  is  a  depres- 
sion in  the  fascia,  opposite  the  inner  inguinal  fossa,  I,  where  the  inter- 
nal inguinal  hernia  begins  to  protrude. 

Internal  abdominal  ring,  F.  This  is  an  elongated  aperture  in  the 
fascia  transversalis,  which  is  external  to  the  epigastric  vessels,  and  little 
above  Poupart's  ligament.  Through  it  pass  the  constituents  of  the- 
spermatic  cord,  viz.  the  spermatic  vessels,  c,  and  their  nerves,  the  duct 
of  the  testis,  K,  part  of  the  genito-crural  nerve,  I,  and  lymphatics:  when 
these  have  reached  the  inside  of  the  abdomen  they  diverge  to  their  des- 
tination beneath  the  peritoneum  and  the  subperitoneal  fat.  Before  the 
dissection  is  made  the  aperture  will  be  closed  by  the  two  internal  strata 
of  the  abdominal  wall,  viz.  subperitoneal  fat  and  peritoneum;  but  in  the 
state  of  the  parts  necessary  for  the  production  of  a  congenital  hernia,  the 
ring  is  not  closed  by  those  layers,  but  remains  patent  for  the  escape  of 
the  gut;  whilst  the  two  strata  (peritoneum  and  subperitoneal  fat)  form 
tubes  which  reach  to  the  testicle  and  are  ready  to  receive  the  descending 
intestine. 

In  an  external  inguinal  hernia  the  piece  of  intestine  leaves  the  abdom- 
inal cavity  through  this  hole,  and  protrudes  along  the  spermatic  cord. 
Of  necessity  the  gut  will  force  onwards,  and  make  coverings  for  itself  of 
the  peritoneum  and  the  subperitoneal  fat,  as  already  said  (p.  39),  before 
it  receives  the  other  coverings  from  the  abdominal  wall. 

The  fascia  iliaca,  D,  covers  the  iliacus  muscle,  and  lies  beneath  the 
large  external  iliac  bloodvessels.  At  Poupart's  ligament  it  joins  the 
fascia  transversalis  as  far  inwards  as  B:  but  thence  to  Gimbernat's  lisra- 
ment  it  is  prolonged  beneath  the  iliac  artery  and  vein,  and  blends  with 
the  hinder  part  of  the  loose  crural  sheath  on  the  femoral  vessels. 

The  crural  sheath  (Plate  xliii.)  is  continuous  above  with  the  fasciae 

just  noticed,  the  fascia  transversalis  entering  the  front,  and  the  fascia 

iliaca  the  back  of  the  tube.     In  it  are  lodged  the  great  vessels,  a  and  i, 

of  the  limb;  and  as  these  occupy  only  the  outer  part  of  the  sheath  in 

consequence  of  the  shape  of  the  parts,  an  interval  is  left  between  the  iliac 

vein,  i,  and   Gimbernat's  ligament,  which  is  named  the  crural  canal. 

The  canal  gradually  tapers  from  above  down,  and  reaches  but  a  short 
4 


50  ILLUSTRATIONS    OF    DISSECTIONS. 

distance  along  the  crural  slieatli:  its  opening  into  the  abdomen  is  called 
the  crural  ring.  A  femoral  hernia  passes  through  this  space  or  passage 
in  the  crural  sheath. 

The  crural  ring,  G,  is  the  aperture  of  entrance  into  the  crural  canal 
from  the  cavity  of  the  abdomen.  About  as  large  as  the  tip  of  the  fore 
finger,  and  flattened  like  this  from  before  back,  it  is  bounded  in  front  by 
Poupart's  ligament  and  the  subjacent  band  of  the  deep  crural  arch; 
behind  by  the  pubes  covered  by  the  pectineus  muscle  and  fascia  lata; 
internally  by  the  base  of  Gimbernat's  ligament,  C;  and  externally  by  the 
iliac  vein,  h.  Of  these  boundaries  only  the  anterior  and  inner  are  un- 
yielding and  sharp  enough  to  constrict  a  piece  of  gut  lying  in  it.  If  the 
fore  finger  is  placed  in  the  ring  whilst  the  hip-joint  is  alternately  flexed 
and  extended  the  influence  of  the  state  of  the  limb  on  the  margins  of  the 
ring  will  be  perceived:  forlaxnessof  Poupart's  and  Gimbernat's  ligament 
will  be  Induced  by  raising  the  thigh,  and  tightness  of  those  bands  will 
follow  straightening  of  the  limb. 

The  ring  is  filled  by  a  lymphatic  gland,  and  transmits  lymph-vessels 
from  the  thigh  to  the  abdomen.  Towards  the  cavity  of  the  belly  it  is 
closed  by  the  striita  of  the  peritoneum  and  subperitoneal  fat.  But  the 
subperitoneal  layer  is  thickened  over  the  crural  ring,  and  is  jj rejected 
downwards  into  that  aperture,  making  thus  a  partition  between  the 
limb  and  the  abdomen;  and  from  this  arrangement  the  term  septuT)! 
crurale  was  applied  to  it  by  M.  Cloquet. 

Vessels  occupy  the  outer  side  and  the  front  of  the  ring.  In  the  former 
situation  is  the  iliac  vein,  h.  In  the  latter  lie  a  small  pubic  branch,/,  of 
the  epigastric  vessels,  and  deeper  amongst  the  muscles,  the  spermatic 
vessels  of  the  testis.  Occasionally  the  obturator  artery,  g,  arises  from 
the  epigastric,  c,  above  the  ring,  and  descends  into  the  pelvis  close  to  the 
iliac  vein,  and  along  the  outer  part  of  the  ring.  With  the  same  origin  it 
may  course  to  the  pelvis  along  the  base  of  Gimbernat's  ligament,  at  the 
inner  part  of  the  ring:  when  it  thus  occupies  the  inner  side,  the  ring  will 
be  encompassed  by  vessels  excej)t  at  the  back. 

Ohturator  or  suhjjuhic  aperture.  Below  the  brim  of  the  pelvis  is  a 
third  aperture,  which  transmits  from  the  abdomen  the  obturator  vessels 
and  nerve.  It  is  a  small  oblique  canal  at  the  upper  part  of  the  thyroid 
foramen;  and  it  is  bounded  partly  by  bone,  and  partly  by  the  obturator 
membrane  and  muscles.     Like  the  two  apertures  before  described^  it  is 


ANATOXY  OF  FEMORAL  HERNIA.  51 

separated  from  the   cavity  of  the  abdomen  by  the  loeritonetim  and  the 
subperitoneal  fat. 

Occasionally  a  piece  of  intestine  leaves  the  abdomen  through  this 
hole,  forming  an  obturator  hernia.  In  such  a  case  the  tumor  would  be 
clothed  by  tlic  peritoneum  and  the  subperitoneal  fat,  like  the  other  hcrnife, 
and  it  would  finally  escape  into  the  thigh  under  the  pectinens  muscle. 
Very  commonly  small  joellets  of  fat  from  the  subperitoneal  layer  joroject 
through  the  aj)erture. 


ANATOMY  OF  FEMORAL  HERNIA. 

A  protrusion  of  intestine  below  Poupart's  ligament  to  the  thigh  gives 
rise  to  a  femoral  hernia.  Part  of  the  anatomy  of  the  hernia  can  be 
studied  in  the  abdom^en,  and  part  with  the  lower  limb;  but  only  the 
facts  illustrated  in  this  Plate  of  the  dissection  of  the  groin  will  be  here 
alluded  to. 

Course.  Entering  the  loose  crural  sheath  through  the  crural  ring, 
the  gut  descends  on  the  inner  side  of  the  femoral  vein  along  the  narrow 
space  of  the  crural  canal,  as  far  as  the  saphenous  opening  in  the  fascia 
lata;  at  this  spot  it  escapes  from  its  narrow  passage,  being  directed  forwards 
through  the  saphenous  opening,  and  forms  a  swelling  on  the  surface  of  the 
thigh.  As  it  proceeds  in  its  course  it  displaces,  or  causes  to  be  absorbed 
the  gland  situate  in  the  crural  canal.  Whilst  it  is  in  the  crural  sheath 
the  gut  has  nearly  a  straight  direction,  but  as  it  projects  forwards  to  the 
surface  a  bend  is  formed  at  the  level  of  the  saphenous  opening;  and  as  it 
increases  in  size,  ascending  on  the  abdomen,  a  second  bend  is  produced. 
See  the  description  in  the  thigh.  The  narrowed  part  of  the  tumor  be- 
neath Poupart's  ligament  is  named  the  neck  of  the  hernia. 

Coverings.  The  intestine  pushes  before  it  some  strata  appertaining 
to  the  wall  of  the  belly,  and  others  belonging  to  the  thigh.  The  cover- 
ings derived  from  the  abdomen  are  the  peritoneal  or  the  sac,  and  the  sub- 
peritoneal or  fatty  layer  which  varies  much  in  thickness  in  different  bodies. 
The  limb-coverings  are  obtained  from  the  crural  sheath,  and  the  tegu- 
ments, and  will  be  described  Avith  Plates  xlii.  and  xliii. 

Taxis.  By  the  view  in  the  Plate  it  appears  that  the  return  of  the 
intestine  will  be  retarded  by  the  tendinous  band  of  Poupart's  and  Gimber- 
nat's  ligament,  if  this  is  kept  tight  by  an  extended  state  of  the  thigh;  and 


62  ILLUSTEATIOXS    OF    DISSECTIONS. 

therefore  the  thigh  should  he  raised  and  rotated  inwards  to  relax  to  the 
utmost  that  band  during  the  employment  of  the  taxis. 

Strichire.  Strangulation  of  the  intestine  takes  place  most  commonly 
in  the  neck  of  the  rupture.  It  may  be  outside  the  sac,  and  be  caused  by 
a  fibrous  band,  or  by  the  sharp  tendinous  edge  of  Poupart'.s  and  Gimber- 
nat's  ligament;  or  it  may  be  placed  inside  the  sac,  being  produced  by 
thickened  j^eritoneum. 

Division  of  the  stricture.  When  all  attempts  to  relieve  the  constric- 
tion of  the  gut,  by  cutting  fibrous  bands  external  to  the  neck  of  the  sac, 
have  failed,  the  sac  will  have  to  be  opened,  and  the  knife  introduced 
under  Poupart's  ligament  into  the  lower  part  of  the  belly.  In  dividing 
the  internal  stricture  the  edge  of  the  knife  should  be  turned  inwards  be- 
cause the  inner  side  of  the  crural  ring  is  usually  free  from  any  blood- 
YBSsel;  liut  the  cutting  instrument  should  not  be  introduced  farther  than 
is  necessary,  for  if  the  bladder  is  distended,  so  as  to  project  above  the  level 
of  the  brim  of  the  pelvis,  it  may  be  injured. 

Occasionally  the  obturator  artery  lies  along  the  inner  side  of  the 
crural  ring  (p.  50).  When  this  unusual  condition  exists  the  vessel  is 
close  inside  the  neck  of  the  hernia,  and  would  most  probably  be  cut  Dy 
the  knife  carried  inwards  as  above  directed.  Fortunately  this  exceptional 
state  is  very  rare  in  conjunction  with  a  hernia  requiring  an  operation  for 
the  relief  of  strangulation  inside  the  neck  of  the  sac. 


EXTERNAL  ILIAC  VESSELS. 

The  topographical  anatomy  of  the  lower  half  of  the  external  iliac 
vessel, — the  part  of  the  artery  to  which  a  ligature  may  be  apphed— is 
represented  in  this  Illustration. 


a.  External  iliac  artery. 
h.  External  iliac  vein. 

c.  Spermatic  artery. 

d.  Circumflex  iliac  artery. 

e.  Epigastric  artery. 

/.  Pubic  branches  of  epigastric. 


g.  Obturator  artery. 

h.  Epigastric  vein. 

i.  Circumflex  iliac  vein, 

fc.  Obturator  vein. 

I.  Spermatic  vein. 


The  external  iliac,  a,  is  the  beginning  of  the  main  artery  of  the  lower 
limb,  and  is  contained  in  the  cavity  of  the  abdomen.  It  reaches  from 
the  base  of  the  sacrum  to  the  lower  border  of  Poupart's  ligament,  where 


LIGATURE    OF    THE    ILIAC    ARTERY.  53 

it  receives  the  name  *'  femoral."  It  has  a  straight  course  above  the  brim 
of  the  pelvis,  and  takes  the  psoas  muscle  as  its  guide. 

In  all  its  extent  the  vessel  is  covered  by  the  peritoneum  and  the  sub- 
peritoneal fat;  and  it  is  accompanied  by  a  chain  of  lymphatic  glands  on 
the  inner  side  and  the  fore  part.  Towards  its  lower  end  numerous  smaller 
vessels  lie  on  it;  thus  the  spermatic  artery  and  veins,  c,  and  the  genital 
branch,  1,  of  the  genito-crural  nerve  pass  along  it;  crossing  over  its  inner 
side  for  a  short  distance  is  the  vas  deferens  of  the  testis,  K;  and  directed 
transversely  over  it  near  its  ending  is  the  circumflex  iliac  vein,  i.  To  its 
inner  side,  and  taking  a  deeper  position  than  it,  is  the  external  iliac  vein, 
J;  but  on  the  right  side  there  is  a  slight  difference  in  the  position  of  the 
vein  (Plate  xxxvi.). 

Two  branches  for  the  wall  of  the  abdomen,  viz.,  circumflex  iliac  and 
ejiigastric,  arise  from  the  lower  end  of  the  vessel. 

Ligature  of  the  artery.  The  slight  depth  of  the  external  iliac  and 
the  small  disturbance  of  the  contents  of  the  abdomen  in  an  attempt  to 
reach  it,  render  practicable  the  ligature  of  this  vessel  by  cutting  through 
the  wall  of  the  belly  in  the  groin. 

Not  to  displace  unnecessarily  the  peritoneum,  the  ligature  should  be 
kept  as  near  as  it  can  be  to  Poupart's  ligament;  but  the  exact  si^ot  to  be 
selected  for  the  ajoplication  of  the  thread  will  be  determined  by  the  posi- 
tion of  the  branches.  Usually  two  branches  arise  near  the  end  of  the 
artery,  and  on  opposite  sides  of  it;  and  if  the  position  of  these  vessels  was 
constant  the  trunk  might  be  tied  about  an  inch  higher  \r^.  But  as  these 
branches  take  origin  at  different  distances  (one  to  two  inches,  Quain) 
from  Poupart's  ligament,  and  as  the  obturator  artery  may  be  attached 
also  to  the  lower  half  of  the  iliac  trunk,  the  spot  selected  for  ligature 
should  be  one  inch  and  a  half  to  two  inches  above  the  crural  arch. 

The  operation  may  be  practised  in  this  manner.  A  cut  is  to  be  made 
through  the  integuments  of  the  Avail  of  the  belly  in  the  groin  from  a  point 
a  little  above  and  outside  the  internal  abdominal  ring  to  the  front  of  the 
iliac  crest;  but  on  the  right  side  the  cut  will  be  reversed.  The  three 
muscular  strata  are  divided  successively  down  to  the  yellow-looking  fascia 
transversalis,  L;  and  then  this  thin  membrane  may  be  slit  on  a  director. 
Next,  the  peritoneum  and  the  subperitoneal  fat  are  to  be  detached  care- 
fully with  the  finger,  without  rupture,  from  the  iliac  fossa.  On  looking 
into  the  wound,  with  the  light  falling  into  it,  the  artery  will  be  seen  in 
the  bottom:  and  after  slightly  detaching  the  iliac  trunk  from  the  sur- 


54:  ILLUSTKATIONS    OF   DISSECTIONS. 

rounding  parts,  a  ligature  may  be  readily  applied  to  it.  Should  tlie 
origin  of  a  branch  come  into  sight  when  the  trunk  is  laid  bare  it  may  be 
included  in  the  thread. 

Difficulty  in  the  execution  of  the  operation  may  be  due  to  enlargement 
of  the  contiguous  inguinal  glands,  which  may  cover  the  arterial  trunk, 
and  would  be  detached  from  it  with  difficulty.  The  following  variation 
in  the  situation  of  the  artery  will  give  rise  to  some  embarrassment  unless 
the  operator  is  previously  acquainted  with  it.  Not  uncommonly  the 
vessel  is  much  bent  downwards  into  the  pelvis,  so  as  to  lie  below  the  brim, 
and  to  be  out  of  sight:  in  such  a  condition  the  artery  would  have  to  be 
raised  to  its  usual  level  by  the  fore  finger  introduced  into  the  wound, 
before  a  ligature  could  be  passed  around  it.  Sometimes  also  in  detaching 
the  subperitoneal  fat  the  external  iliac  is  raised  from  its  usual  situation, 
and  is  carried  upwards  with  that  layer:  when  this  displacement  occurs 
the  vessel  may  be  detected  in  the  fatty  layer  by  means  of  the  pulsation. 

Branches  of  the  iliac.  The  two  branches  of  the  artery  ramify  in  the 
Avail  of  the  belly,  one  in  the  front,  and  the  other  behind.  Only  the  be- 
ginning of  those  branches  can  be  now  seen. 

The  epigastric  artery,  e,  ascends  on  the  inner  side  of  the  internal  ab- 
dominal ring  to  the  rectus  muscle.  At  first  it  lies  beneath  the  fascia 
transversalis,  but  finally  perforates  this  membrane  to  enter  the  sheath 
of  the  rectus.  On  each  side  of  the  artery  lies  a  vein;  these  join  below 
into  one. 

Small  branches,  puhic,  run  inwards  to  the  back  of  the  pubes,  anasto- 
mosing with  their  fellows,  and  the  obturator,  g.  Cremasteric  offsets  (p. 
38)  are  supplied  to  the  muscular  covering  of  the  cord. 

The  circumflex  iliac  artery,  d,  is  directed  to  the  iliac  fossa  below 
Poupart's  ligament  (Plate  xxxvi.).  Small  muscular  branches  are  given 
by  it  to  the  abdominal  wall  and  the  iliacus. 

Two  other  small  arteries,  the  spermatic  and  obturator,  come  into  the 
dissection  for  a  short  distance. 

The  spermatic  artery,  c,  a  branch  of  the  aorta,  courses  to  the  testis 
through  the  internal  abdominal  ring.  The  veins  accompanying  it  unite 
together  higher  in  the  abdomen  (Plate  xxxvi.). 

The  obturator  artery,  g,  arises  from  the  internal  iliac  trunk  in  the 
pelvis,  and  issues  through  the  subpubic  aperture  to  the  thigh.  Its  com- 
panion vein,  Tc,  and  nerve,  4,  have  a  like  course. 


-:fS0''-" 


PLATE  XXXVI. 


•V 


I  ..f 


^7  ,   /IAa 


J  '^ 


1/     ' 


"  '  p  mm  ' 


\nVV 


/' 


MUSCLES    IN    THE    ABDOMINAL    CAVITY.  55 

The  nerves  in  the  dissection  are  offsets  of  the  lumbar  plexus,  and  are 
represented  more  fully  in  the  two  following  Plates. 


1.  Genital  brancli  of  genito-crural. 

2.  Crural  branch  of  genito-ci-ural. 


3.  External  cutaneous  nerve. 

4.  Obturator  nerve. 


The  genito-crural  nerve  divides  into  two: — The  genital  branch,  1, 
runs  on  the  external  iliac  artery,  and  issues  through  the  internal  abdo- 
minal ring  to  supply  the  cremaster  muscle;  the  crural  branch,  3,  passes 
beneath  Poupart's  ligament  to  the  integuments  of  the  thigh. 

The  external  cutaneous,  3,  is  directed  under  the  outer  end  of  Pou- 
part's ligament  to  the  teguments  of  the  thigh. 

The  obturator  nerve,  4,  escapes  from  the  abdomen  by  the  subpubic 
hole  with  the  vessels  of  the  same  name,  above  which  it  lies:  it  is  distri- 
buted in  the  thigh. 


DESCRIPTION  OF  PLATE  XXXVI. 


The  deep  muscles  and  the  vessels  of  the  abdominal  cavity  are  figured 
in  this  Plate. 

The  objects  here  represented  will  be  readily  cleaned  after  the  removal 
of  the  viscera  from  the  cavity  of  the  abdomen;  but  as  the  large  vein 
(vena  cava)  is  imbedded  in  the  substance  of  the  liver  it  is  usually  cut 
away  in  the  removal  of  that  viscus.  To  denude  the  diaphragm,  dissect 
off  with  care  the  peritoneum;  to  remove  that  membrane  from  the  tendon 
of  the  muscle,  to  which  it  adheres  closely,  will  require  some  skill  on  the 
part  of  the  dissector. 

On  the  right  side  the  deep  muscles  are  to  be  laid  bare,  but  on  the  left 
the  fascia  covering  them  may  remain  entire. 

The  small  nerves  issuing  from  the  substance  of  the  psoas  muscle  lie  in 
a  loose  fat,  and  can  be  defined  with  ease. 

MUSCLES  IN  THE  ABDOMINAL  CAVITY. 

One  of  the  muscles  (diaphragm)  separates  the  cavities  of  the  thorax 
and  abdomen,  and  is  used  in  respiration;  the  others,  placed  on  the  side 


56 


ILLU8TKATION8    OF    DISSECTIONS. 


of  the  spine,  take  part  in  the  movements  of  the  lower  limb  and  the  last 
rib. 


A,  Fleshy  part  of  the  diaphragm. 

B.  Mid-part  of  the  tendon. 
C  Left  piece  of  the  tendon. 

D.  Right  piece  of  the  tendon. 

E.  Right  crus. 

F.  Left  crus. 

G.  Internal  arched  ligament. 
H.  External  arched  ligament. 
I.    Quadratus  lumborum, 

J.    Psoas  parvus  muscle. 


K.  Psoas  magnus. 

L.  Iliacus  muscle. 

M.  Urinary  bladder. 

N.  Rectum. 

O.  Vas  deferens  of  the  testis. 

P.  Left  ureter. 

Q.  Left  kidney. 

R.  Supra-renal  body. 

S.  CEsophagus,  cut. 

T.  Pectineus  muscle. 


The  diaphragm,  A,  stretches  across  the  hollow  included  by  the  ribs, 
And  divides  this  space  into  two, — an  upper  part,  cavity  of  the  thorax,  and 
a  lower  or  abdominal  cavity.  The  muscle  is  fleshy  at  the  circumference 
where  it  is  fixed  to  the  ribs,  and  tendinous  in  the  centre. 

The  diaphragm  takes  origin  externally,  on  each  side,  from  the  back 
of  the  xiphoid  cartilage;  from  the  six  lower  ribs  on  the  inner  surface;  from 
the  two  arched  ligaments,  H  and  G;  and  from  the  side  of  the  spinal 
column  by  the  crus,  E.  All  the  fleshy  fibres  end  internally  in  the  central 
tendon,  to  which  they  are  directed  with  varying  lengths  and  inclina- 
tions. 

It  is  arched  unequally  on  the  two  sides,  being  highest  on  the  right. 
Its  surfaces  look  uj)wards  and  downwards  to  the  thoracic  and  abdominal 
cavities;  and  they  differ  in  form,  for  the  upper  is  convex,  and  the  lower 
concave.  In  contact  with  the  ujoper  are  the  viscera  and  membranes  of 
the  thorax;  and  the  lower,  clothed  by  the  peritoneum,  touches  the  larger 
viscera  in  the  abdominal  cavity.  Three  large  tubes — two  for  the  convey- 
ance of  blood  (aorta  and  cava),  and  one  of  the  food  (oesophagus) — pass 
through  the  muscle;  and  smaller  apertures  for  the  transit  of  vessels  and 
nerves  exist  on  each  side.  In  the  dead  body  the  muscle  is  arched  higher 
on  the  sides  than  in  the  centre,  and  the  bulge  on  the  right  is  higher 
than  that  on  the  left.  The  right  curve  descends  as  high  as  the  upper  bor- 
der of  the  cartilage  of  the  fifth  rib  near  the  sternum,  and  the  left  reaches  in 
like  manner  to  the  level  of  the  sixth  rib.  By  the  action  of  this  muscle 
the  cavities  of  the  abdomen  and  thorax  are  enlarged  and  diminished,  and 
the  viscera  are  compressed  and  relaxed  alternately. 

During  contraction  or  shortening  of  the  fibres  the  muscle  moves  down 


MUSCLES    IN    THE    ABDOMINAL    CAVITY.  57 

slio-litly  in  the  cavity  of  the  abdomen,  diminishing-  this  space  andenlarg- 
ino-  the  thorax;  and  as  the  fleshy  or  lateral  part  moves  more  than  the 
central  or  tendinous  the  whole  muscle  resembles  in  form  aflat-roofed  tent. 
In  consequence  of  an  increase  in  the  size  of  thorax  during  its  contraction 
it  acts  as  an  inspiratory  muscle.  By  tlie  descent  above  indicated  the 
viscera  in  the  upper  part  of  the  abdomen  are  forced  down;  and  if  the 
diaphragm  be  fixed  in  that  position,  whilst  the  abdominal  muscles  are 
contracted,  the  viscera  will  be  compressed  between  the  two,  and  the  con- 
tents of  some  may  be  expelled. 

"When  the  shortened  fibres  relax  and  lengthen  the  muscle  is  moved 
one  rib  higher  on  both  sides  than  its  level  in  the  dead  body;  and  it  dimin- 
ishes in  this  way  the  cavity  of  the  thorax,  whilst  it  increases  proportionally 
that  of  the  abdomen.  By  causing  a  decrease  in  the  cavity  of  the  thorax 
it  becomes  an  expiratory  muscle.  In  its  ascent  the  viscera  of  the  thorax 
are  raised,  especially  the  heai-t,  and  those  in  the  abdomen  regain  their 
usual  place. 

Named  parts  of  the  muscle.  These  are  three,  viz.,  the  central  tendon, 
the  pillars,  and  the  arched  ligaments. 

The  central  tendon,  not  attached  to  bone,  is  a  thin  aponeurotic  layer, 
which  is  shaped  like  a  trefoil  leaf,  and  has  been  called  heart-shaped  or 
cordiform.  It  receives  by  its  circumference  the  fleshy  fibres,  and  is 
pierced  by  the  large  inferior  cava:  it  is  divided  into  three  pieces; — a  cen- 
tral, B;  a  left  narrow  portion,  C;  and  a  right  piece,  D. 

The  crura  or  ^jillars  lie  on  the  sides  of  the  aorta,  a,  and  form  two 
thick  fleshy  bundles,  which  are  fixed  by  tendon  to  the  subjacent  lumbar 
vertebrae  and  their  intervertebral  substance.  Of  the  two,  the  right  crus 
is  larger  than  the  left,  and  in  the  succeeding  Plate  it  may  be  seen  more 
distinctly.  From  the  tendinous  part  the  fleshy  fibres  ascend  to  the  central 
tendon,  but  the  most  internal  set  pass  between  the  aorta  and  the  oesopha- 
gus, decussating  with  their  fellows,  and  bound  laterally  the  oesophagean 
opening  in  their  upward  course  to  tlieir  destination.  Most  commonly 
the  fasciculus  of  the  right  side  is  anterior  to  that  of  the  left  at  the 
point  of  crossing. 

The  arched  ligaments  are  fibrous  bands  over  the  loin-muscles  for  the 
purpose  of  giving  attachment  to  the  hinder  fibres  of  the  diaphragm. 

The  internal  one,  G-  (ligam.  arcuat.  intern.),  the  longest  and  most 
curved,  lies  over  the  psoas  muscle.  By  the  inner  end  it  joins  the  tendin- 
ous part  of  the  crus,  and  by  the  outer  it  is  inserted  into  the  transverse 


58  ILLUSTRATIONS    OF    DISSECTIONS. 

process  of  .the  first  lumbar  vertebra.  The  external  band,  H  (lig.  arc. 
extern.),  is  attached  externally  to  the  last  rib,  and  internally  it  blends  with 
the  inner  ligament :  it  is  placed  over  the  quadratus  muscle,  I,  and  under 
or  through  it  the  last  dorsal  nerve  and  the  accompanying  vessels  issue. 

AjJertures  in  the  diaphragm.  Three  large  central  holes  give  passage 
to  the  oesophagus  and  the  two  large  bloodvessels  of  the  lower  half  of  the 
body;  and'  on  each  side  of  the  aorta  is  a  fissure  in  the  crus  for  the  trans- 
mission of  the  splanchnic  nerves. 

The  msophagean  opening  occupies  the  fleshy  part  of  the  muscle 
behind  the  central  tendon.  It  is  placed  in  front  of  the  spinal  column, 
above  and  to  the  left  of  the  aortic  opening.  Its  bounding  fibres  are 
derived  from  the  crura,  those  on  the  left  side  coming  from  the  right  crus; 
and  the  opposite.  Through  this  aperture  are  transmitted  the  oesophagus, 
and  the  two  pneumo-gastric  nerves,  with  areolar  tissue.  It  is  larger  than 
the  tube  passing  through;  and  it  will  be  reduced  in  size  by  the  contraction 
of  the  fleshy  fibres. 

The  opening  for  the  vena  cava  (for.  quadratum)  lies  on  tlie  right  of 
the  oesophagean,  and  higher  than  it.  It  is  situate  in  the  central  tendon 
near  the  back  part.  Its  margins  blend  with  the  coat  of  the  vein,  except  on 
the  inner  side;  and  its  size  will  not  be  diminished  during  the  contraction 
of  the  fleshy  fibres  of  the  diaphragm.  It  gives  passage  to  the  vena  cava 
inferior,  and  some  areolar  tissue. 

The  aortic  opening  is  rather  behind  than  in  the  diaphragm,  and  is  oppo- 
site the  last  dorsal  vertebra.  Laterally  it  is  bounded  by  the  pillars  of  the 
diaphragm;  and  in  front  by  a  narrow  tendinous  band  which  intervenes 
between  the  crura.  Through  it  pass  the  aorta,  the  thoracic  duct,  and 
the  large  azygos  vein,  with  areolar  tissue. 

The  fissure  for  the  splanchnic  nerves  (Plate  xxxvii.)  lies  in  the  fleshy 
part  of  the  crus,  and  transmits  on  the  right  side  the  splanchnic  nerves. 
Through  that  on  the  left  side,  besides  the  three  corresponding  nerves, 
passes  the  small  azygos  vein. 

The  psoas  magnus  muscle,  K,  occupies  the  loms,  and  leaves  the  abdo- 
men beneath  Poupart's  ligament  to  be  attached  to  the  femur  with  the 
iliacus. 

The  muscle  arises  from  the  bodies  of  the  lumbar  vertebrae  and  their 
intervertebral  substance;  from  the  body  of  the  last  dorsal;  and  from  the 
transverse  processes  in  the  loins  by  aponeurotic  slips.     Inferiorly  it  ends 


MUSCLES    IN    THE    ABDOMINAL    CAVITY.  59 

in  a  tendon,  which  is  continued  to  the  thigli,  and  is  inserted  into  the 
sniiiU  trochanter  of  the  femur. 

The  psoas  lies  beneath  tlie  kidney  and  tlie  ureter  and  tlie  spermatic 
vessels.  At  the  attachment  to  the  lumbar  vertebrae  fibrous  arches  span 
ovei'  the  lumbar  vessels;  and  along  its  inner  edge  below  the  spinal  column 
rest  the  external  iliac  vessels.  The  outer  edge  overlays  the  quadratus 
lumborum,  I,  and  the  iliacus,  L,  and  some  nerves  of  the  lumbar  plexus. 

If  the  femur  is  free  to  be  moved  this  muscle  Avill  raise  it  towards  the 
abdomen,  bending  the  hip-Joint,  and  afterwards  will  rotate  out  the  limb. 
When  the  limb  is  immovable,  as  when  it  supports  the  weight  of  the  body, 
the  muscle  will  draw  forwards  the  trunk  over  the  femur,  as  in  stooping. 
In  standing  the  lumbar  part  of  the  spine  is  kept  erect  by  the  action  of 
both  muscles;  or  is  bent  to  the  side  by  one. 

The  psoas  jJcirvus  muscle,  J,  appears  to  be  but  a  part  of  the  large  psoas: 
it  is  often  absent.*  It  takes  origin  from  the  bodies  of  the  last  dorsal  and 
first  lumbar  vertebrae,  and  from  their  intervertebral  substance;  audit  ends 
below  in  a  strong  tendon,  which  is  inserted  into  the  fore  jiart  of  the  brim 
of  the  pelvis,  blending  with  the  iliac  fascia.  Near  the  ribs  the  muscle 
lies  on  the  psoas  magnus,  but  slips  to  the  inner  side  of  this  muscle  below. 

As  the  muscle  is  not  fixed  to  the  femur  it  cannot  act  on  the  hip-joint. 
In  the  recumbent  posture  it  may  raise  forwards  the  pelvis;  and  in  standing 
it  assists  the  large  psoas  in  supporting  and  bending  forwards  the  lumbar 
part  of  the  spine. 

Quadratus  lumborum,  I.  This  muscle  fills  the  space  between  the  last 
rib  and  the  iliac  crest,  and  is  best  displayed  in  Plate  xxxvii.  Two  to 
three  inches  wide  below,  the  muscle  arises  from  the  ilio-vertebral  liga- 
ment, and  the  crest  of  the  hip-bone  behind  that  baud:  it  is  inserted 
internally  into  the  transverse  processes  of  the  four  upper  or  all  the  lum- 
bal- vertebrae,  and  into  the  last  rib  and  the  body  of  the  last  dorsal  vertebra. 

The  quadratus  is  partly  concealed  by  the  psoas,  and  is  contained  in  a 
sheath  derived  from  the  fascia  lumborum.  Nerves  from  the  lumbar  plexus 
cross  it,  and  the  last  dorsal  nerve  lies  along  the  outer  edge. 

When  the  muscle  acts  from  the  pelvis  it  can  render  firm  the  last  rib 
so  as  to  give  a  fixed  point  for  the  action  of  the  diaphragm  in  deep  inspi- 
ration.    If  both  muscles  act  on  the  spine  they  will  assist  the  psoas  muscles 

*  This  muscle  was  found  but  once  in  twenty  bodies  which  were  examined 
carefully  by  TheUe.     "  Lelire  von  den  Muskeln."    Leipzig,  1841. 


60 


ILLUSTRATIONS    OF    DISSECTIONS. 


in  maintaining  it  erect;  but  if  only  one  is  active  the  spine  will  be  inclined 
towards  the  same  side.  In  climbing  it  will  assist  the  abdominal  muscles 
in  raising  the  pelvis. 

The  iliacus  muscle,  D,  arises  from  the  iliac  fossa  of  the  hip-bone,  and 
from  the  base  of  the  sacrum;  from  the  ilio-vertebral  ligament  behind;  and 
from  the  capsule  of  the  hip-joint  in  front.  Many  of  the  fibres  join  inter- 
nally the  tendon  of  the  psoas  muscle,  but  the  rest  pass  beneath  Poupart's 
lisrament,  and  are  inserted  into  the  femur  in  front  of,  and  below  the 
small  trochanter. 

On  the  right  muscle  rests  the  caecum,  and  on  the  left  the  sigmoid 
flexure  of  the  colon.  Below  the  pelvis  the  muscle  covers  the  hip-joint; 
and  as  it  passes  over  the  anterior  edge  of  the  hip-bone,  a  small  bursa  lies 
underneath  it. 

If  the  lower  limb  is  free  the  iliacus  assists  the  psoas  in  flexing  the  hip- 
joint;  and  if  the  limb  is  fixed  the  muscle  will  bring  forwards  the  pelvis  on 
the  head  of  the  femur. 

LympTiatic  glands,  f  f .  A  chain  of  glands  lies  by  side  of  the  large 
bloodvessels.  Erom  these  glands  small  efferent  vessels  are  continued  up- 
wards to  unite  with  the  thoracic  duct  near  the  beginning  (P'ate  xxxvii.). 


BLOODVESSELS  OF  THE  ABDOMEN. 

A  large  arterial,  and  a  venous  trunk  traverse  the  abdomen: — the 
former  (aorta)  supplies  offsets  in  the  cavity,  and  a  large  vessel  to  each 
limb:  the  latter  (vena  cava),  formed  by  the  union  of  two  large  veins,  one 
from  each  limb,  gathers  smaller  branches  from  the  abdominal  walls  and 
the  viscera. 


a.  Aorta. 

h.  Common  iliac  artery. 

c.  Internal  iliac  artery. 

d.  External  iliac  artery. 

e.  Diaphragmatic  artery. 
/.  Coeliac  axis. 

(J.  Upper  mesenteric  artery. 

11.  Renal  artery. 

i.    Spermatic  artery. 

j.    Supra- renal  artery. 

k.  Inferior  mesenteric  artery. 

I.  Lumbar  arteries. 


n.  Middle  sacral  artery. 

j9.  Vena  cava  inferior. 

q.  Common  iliac  vein. 

r.  External  iliac  vein. 

s.   Lowest  intercostal  artery. 

t.    Renal  vein. 

u.  Supra-renal  vein. 

V.  Spermatic  vein. 

w.  Lumbar  vein. 

X.  Middle  sacral  vein. 

y.  Circumflex  iliac  artery. 


AQRTA    AND    ITS    BRANCHES.  61 

The  aorta,  a,  the  miiiu  vessel  of  the  body,  extends  through  the  thorax 
and  abdomen.  The  part  in  the  hitter  cavity  is  called  abdominal,  and 
reaches  from  the  opening  in  the  diaphragm  to  the  left  side  of  tlie  fourtli 
lumbar  vertebra,  where  it  bifurcates  into  tlie  common  iliac  arteries,  h. 
This  large  trunk  rests  on  the  vertebral  column  behind  the  viscera  and  the 
peritoneum,  and  is  crossed  by  the  left  renal  vein,  t.  Its  offsets  are  vis- 
ceral and  parietal. 

The  visceral  branches  aa-e  the  following:  three  spring  from  the  front 
of  the  vessel,  viz.,  coeliac  axis/,  upper  mesenteric  g,  and  inferior  mesen- 
teric k;  and  three  pairs  of  branches,  which  come  from  the  sides,  are  the 
supra-renal  /,  the  renal  h,  and  the  spermatic  i.  Only  the  lateral  visceral 
branches  remain  in  the  dissection,  the  former  set  having  been  cut  neces- 
sarily in  the  removal  of  the  viscera. 

The  renal  artery,  h,  is  directed  almost  horizontally  outwards  to  the 
kidney,  and  divides  near  that  viscus  into  branches  which  enter  it  between 
the  vein  and  ureter.  The  artery  of  the  left  side  is  not  so  long  as  that  on 
the  right. 

The  supra-renal  or  middle  capsular  artery,  /,  taking  the  same  direc- 
tion as  the  renal,  enters  the  supra-renal  body.  In  the  foetus  it  is  larger 
than  in  the  adult. 

The  sjjermatic  artery,  i,  arises  near  the  renal  (the  testicle  developing 
in  the  loins),  and  descends  over  the  psoas  and  the  external  iliac  artery  to 
the  internal  abdominal  ring:  at  this  spot  it  leaves  the  abdomen  to  reach 
the  testicle.     On  the  right  side  the  artery  crosses  the  vena  cava. 

Originally  the  spermatic  vessels  were  short  and  straight,  like  the 
renal,  but  their  increase  in  length  is  brought  about  by  the  testicle  passing 
from  the  place  of  growth  in  the  abdomen  to  the  scrotum. 

Parietal  Iranches.  The  arteries  that  are  furnished  to  the  wall  of  the 
belly  are  the  diaphragmatic,  the  lumbar,  and  the  middle  sacral. 

The  cliapJiragmatic,  e,  are  the  first  two  branches  of  the  aorta  in  the 
abdomen,  and  ramify  on  the  under  surface  of  the  diaphragm.  Each 
courses  over  the  fleshy  fibres  of  the  muscle  to  the  front,  and  furnishes  an 
offset  towards  the  hinder  part. 

The  lumbar  arteries,  I,  four  in  number  on  each  side,  arise  from  the 
back  of  the  aorta,  and  correspond  with  the  intercostals  in  the  thorax: 
their  distribution  is  more  evident  in  Plate  xxxvii. 

The  middle  sacral  artery,  n,  arises  from  the  point  of  splitting  of  the 
aorta,  and  descending  beneath  the  left  common  iliac  vein,  runs  along  the 


62  ILLUSTRATIONS    OF    DISSECTIONS. 

middle  of  the  sacrum  to  the  end  of  the  spinal  column.  Small  offsets  are 
supplied  from  it  opposite  each  yertebra. 

The  common  iliac  artery,  h,  is  the  primary  trunk  derived  from  the 
bifurcation  of  the  aorta.  About  two  inches  in  length  it  reaches  as  far  as 
the  fibro-cartilage  between  the  last  lumbar  vertebra  and  the  base  of  the 
sacrum:  at  this  spot  it  ends  by  dividing  into  external  and  internal  iliac 
arteries.  Of  the  two  vessels  the  right  is  more  oblique  in  direction,  and 
longer  than  the  left.  Each  artery  lies  against  the  spinal  column,  and  is 
placed  beneath  the  peritoneum,  like  the  aorta;  it  is  crossed  by  several 
offsets  of  the  sympathetic  nerve,  and  sometimes  by  the  ureter,  P. 

On  opposite  sides  of  the  body  its  connections  with  other  vessels  are 
different.  On  the  left,  the  iliac  trunk  is  crossed  by  part  of  the  inferior 
mesenteric  artery,  h;  and  its  companion  vein,  q,  lies  nearer  the  joelvis. 
On  the  right  side  the  iliac  artery  touches  three  large  venous  trunks;  thus 
the  right  common  iliac  vein  is  external  to  it,  the  left  common  iliac  vein 
crosses  beneath  it,  and  the  beginning  of  the  vena  cava  is  placed  on  the 
outer  side  opposite  the  fifth  lumbar  vertebra. 

Only  small  glandular  offsets  are  furnished,  as  a  rule,  by  the  common 
iliac  trunk,  but  a  renal  or  an  ilio-lumbar  artery  will  take  origin  from  it 
occasionally. 

Ligahire. — The  length  of  the  arterial  trunk,  and  the  origin  of 
branches  influence  greatly  the  chances  of  a  successful  ligature  of  it.  If 
the  vessel  is  less  than  an  inch  in  length  it  is  too  short  for  the  application 
of  a  string  without  haemorrhage  ensuing  on  the  separation  of  that  band; 
in  such  a  condition  ligature  of  the  beginning  of  the  external  and  internal 
iliac  would  be  preferable  to  tying  the  trunk  which  is  too  short  (Quain). 
If  during  an  operation  an  uncommon  branch  should  be  seen  to  spring 
from  the  iliac  artery  it  should  be  included  in  the  ligature,  in  order  that 
its  disturbing  influence  on  the  obliteration  of  the  vessel  may  be  removed. 

Internal  iliac  artery,  c.  This  is  the  smallest  of  the  two  vessels  re- 
sulting from  the  bifurcation  of  the  common  iliac  trunk:  it  enters  the 
pelvis,  furnishing  branches  to  that  cavity,  and  is  shown  in  Plate  xxxvii. 

The  external  iliac  artery,  d,  courses  along  the  psoas  muscle  to  the 
lower  limb,  and  reaches  from  the  base  of  the  sacrum  to  the  lower  border 
of  Poupart's  ligament.  Its  position  will  be  marked  on  the  surface  of  the 
abdomen  by  a  line  from  the  left  of  the  umbilicus  to  a  spot  midway  be- 
tween the  symphysis  pubis  and  the  iliac  crest.  Throughout  its  length  it 
is  covered  by  the  peritoneum  and  subperitoneal  fat,  and  a  chain  of  lym- 


ILIAC    ARTERIES    AND    VEINS.  63 

phatic  glands  lies  along  its  side.  Near  Poupart's  ligament  it  is  crossed 
by  several  small  vessels  (p.  53).  On  the  left  side  the  large  intestine 
crosses  the  artery. 

Its  companion  vein  is  internal  on  the  left  sido;  but  on  the  right  side, 
the  vein  is  on  the  inside  near  Poupart's  ligament,  and  on  the  outside  near 
the  sacrum,  crossing  under  the  artery. 

Two  hranches,  epigastric  and  circumflex  iliac,  arise  from  the  artery 
near  the  end:  they  have  beeii  noticed  before  (p.  54).  Ligature  of  the 
vessel  should  be  practised  rather  below  its  middle  (p.  53). 

Muscular  hranches  in  the  abdomen.  In  the  diaphragm  small  ter- 
minal offsets  of  the  intercostal  arteries  ramify,  and  anastomose  with  the 
other  arteries  to  the  muscle.  To  the  quadratus,  I,  and  iliacus,  L, 
branches  of  the  lumbar  and  ilio-lumbar  arteries  are  furnished. 

Abdominal  veins.  Each  of  the  large  arterial  trunks  above  described 
has  its  companion  vein,  whose  anatomy  is  similar  to  that  of  the  artery. 

The  external  iliac,  r,  has  the  same  limits  as  the  artery  of  the  same 
name,  and  is  provided  also  with  two  branches,  viz.,  circumflex  iliac  and 
epigastric.  Its  position  to  the  artery  varies  on  the  two  sides:  thus  the 
left  lies  inside  and  below,  and  the  right  crosses  underneath  its  artery  from 
the  inner  to  the  outer  side. 

The  common  iliac,  q,  is  formed  by  the  union  of  the  pelvic  vein  (inter- 
nal iliac)  and  of  the  lower  limb  vein  (external  iliac);  the  veins  of  oppo- 
site sides  blend  in  the  vena  cava  inferior  opposite  the  last  lumbar  verte- 
bra, so  that  the  veins  do  not  reach  so  high  as  the  arteries  of  the  same 
name.  Two  veins,  ilio-lumbar  and  lateral  sacral,  enter  each  trunk;  and 
the  middle  sacral  is  received  into  the  left  common  iliac. 

The  following  are  the  differences  between  the  veins  of  opposite  sides; 
— In  length  the  left  exceeds  the  right.  In  position  to  the  companion 
bloodvessel  they  vary  on  the  two  sides  of  the  body,  for  instance,  the  right 
is  external  to  and  above  its  artery,  whilst  the  left  lies  below,  and  passes 
also  beneath  the  right  common  iliac  artery. 

The  inferior  cava  (vena  cava  ascendens)  conveys  to  the  heart  the 
blood  of  the  lower  half  of  the  body.  Placed  on  the  right  side  of  the 
spine,  it  begins  opposite  the  body  of  the  fifth  lumbar  vertebra  by  the 
union  of  the  common  iliac  veins,  and  passing  through  the  diaphragm 
enters  the  right  ventricle  of  the  heart:  it  is  therefore  longer  than  its  com- 
panion artery,  the  aorta. 


64: 


ILLUSTEATIOJSrS    OF    DISSECTIONS. 


Covered  in  front  by  the  jieritoneum  like  the  aorta,  it  rests  far  the 
most  part  on  those  branches  of  the  aorta  which  are  directed  to  the  right, 
viz.,  lumbar,  renal,  capsular,  and  diaphragmatic;  but  the  right  spermatic 
crosses  over  it.  For  about  an  inch  and  a  half  from  the  diaphragm  it  is 
surrounded  by  the  liver. 

Its  branches  are  parietal  and  visceral  like  the  offsets  of  the  aorta. 
The  former  set,  tho  smallest,  consists  of  lumbar  and  diaphragmatic. 

Visceral  veins  from  the  alimentary  tube  and  its  glandular  viscera,  and 
corresponding  with  the  coeliac  axis  and  mesenteric  arteries,  do  not  enter 
directly  the  cava,  but  blend  into  one — the  vena  portse.  This  single  trunk 
ramifies  through  the  liver;  and  the  circulating  blood  is  finally  conveyed 
to  the  cava  by  large  veins — vense  cavee  hepaticse — close  to  the  liver.  In 
the  dissection  these  veins  were  necessarily  cut  across  by  the  removal  of 
the  liver. 

The  visceral  veins  from  the  supra-renal  body,  the  kidney,*  and  the 
testicle,  are  received  into  the  cava  as  separate  vessels  on  the  right  side; 
but  the  corresponding  veins  on  the  left  side  join  the  left  renal  vein,  and 
the  blood  from  all  three  is  transmitted  by  this  single  channel  to  the  cava. 

Occasionally  the  cava  lies  on  the  left  of  the  aorta  as  high  as  the  kidney: 
then  receiving  the  left  renal  vein,  it  crosses  the  spine  into  its  usual  place. 

SPINAL  NERVES  IN  THE  ABDOMEN. 

All  the  nerves  now  visible,  except  two,  come  from  the  lumbar  plexus 
in  the  psoas  muscle.  In  the  next  Plate  the  origin  of  the  nerves  from  the 
plexus  is  brought  under  notice. 


1.  Last  dorsal  nerve. 

2.  Ilio-hypogastric  branch. 

3.  Ilio-inguinal  branch. 

4.  Crural  branch  of    genitocrural 

nerve. 


5.  Genital  branch  of  genito-crural. 

6.  External  cutaneous  branch. 

7.  Anterior  crural  nerve. 

8.  Ending  of  phrenic  nerve. 


Branches  of  lumbar  plexus.  The  position  of  the  branches  of  the 
plexus  to  the  psoas  muscle  is  the  following: — Along  the  outer  edge  appear 
four  nerves;  two  at  the  upper  part,  viz.,  the  ilio-hypogastric  and  ilio- 
inguinal; one   about  the  middle — the  external  cutaneous;  and   a  hii-ge 


*The  right  renal  vein  joins  the  cava  frequently  higher  than  the  left:  it  is  also 
the  shortest  of  the  two. 


PLATE  XXXVI 


1  n 


\d  ^ 


V 


1^  *  1*:  A  \ 


7'.^    I 


DEEP   MUSCLES    OF    THE    ABDOMEN.  65 

nerve  below — the  anterior  crural.  Kather  below  the  pelvic  part  of  the 
inner  edge  of  the  muscle  the  obturator  nerve  courses  forwards  (Plate 
xxxvii. ).  Piercing  the  fibres  of  the  muscle  will  be  one  or  two  pieces  of  the 
genito-crural  nerve;  this  difference  depending  upon  the  division  of  the 
nerve  nearer  to,  or  farther  from  its  origin  in  the  plexus. 

All  these  branches  are  distributed  outside  the  cavity  of  the  abdomen, 
ending  in  the  abdominal  wall,  the  lower  limb,  and  the  cutaneous  and 
fleshy  coverings  of  the  spermatic  cord. 

Ending  of  the  'phrenic  nerve,  8.  Some  of  the  terminal  branches  of 
this  nerve  pierce  the  fibres  of  the  diaphragm,  and  run  on  the  under 
surface  of  the  muscle  before  disappearing  in  the  fleshy  fibres.  On  the 
abdominal  surface  of  the  muscle  they  communicate  with  branches  of  the 
sympathetic  nerve  forming  a  plexus.  At  the  place  of  union  a  ganglion 
exists  on  the  right  side  (Swan). 

Last  dorsal  nerve,  1.  This  trunk  appears  below  the  last  rib,  and 
enters  the  wall  of  the  belly  to  be  distributed  in  it,  like  the  other  inter- 
costal nerves:  it  can  be  seen  more  plainly  in  the  following  Plate. 


DESCRIPTION  OF  PLATE  XXXVII. 


This  Illustration  shows  the  dissection  of  the  lumbar  and  sacral  plex- 
uses of  spinal  nerves,  and  that  of  the  internal  iliac  artery.* 

For  the  preparation  of  the  parts  displayed  the  psoas  muscle  and  the 
veins  of  the  right  side  of  the  abdomen  were  taken  away;  the  external 
iliac  vessels  were  cut  through  and  removed;  and  the  peritoneum  and 
fat,  and  the  internal  iliac  vein  and  its  branches,  were  cleared  from  the 
pelvis. 

DEEP  MUSCLES  OF  THE  ABDOMEN. 

The  muscles  now  brought  into  view  were  referred  to  in  detail  in  the 
last  Plate,  but  the  quadratus  lumborum  can  be  better  learnt  in  this 


*  Usually  the  lumbar  plexus  and  the  internal  iliac  artery  are  dissected  on 

opposite  sides  of  the  body,  but  both  have  been  here  joined  in  one  view  on  the 

right  side,  so  as  not  to  increase  unnecessarily  the  number  of  Plates. 
5 


66 


ILLUSTRATIONS    OF    DISSECTIONS. 


Figure.  Only  a  small  part  of  the  diaphragm,  C,  has  been  left;  and  the 
right  crus  has  been  cut  through  to  allow  the  beginning  of  the  thoracic 
duct,  and  the  large  azygos  vein  to  be  seen. 


A.  Right    crus  of    the    diaphragm 

divided. 

B.  Left  cms  of  the  muscle. 

C.  Fleshy  lateral  part  of  the  dia- 

phragm. 

D.  External  arched  ligament. 


E.  Twelfth  rib,— right. 

F.  Quadratus  lumborum. 

G.  Iliacus  muscle. 

H.  Psoas  muscle,  cut. 

I.    Ilio-vertebral  ligament. 

K.  Urinary  bladder. 


ABDOMINAL  AND  PELVIC  ARTERIES. 

In  this  Plate  the  aorta  is  represented  in  outline  with  the  origin  of  the 
visceral  branches;  and  its  lumbar  offsets  are  traced  back  to  their  exit 
from  the  abdomen.  In  the  cavity  of  the  pelvis  the  internal  iliac  artery 
and  'its  branches  are  displayed;  and  in  the  aortic  opening  of  the  dia- 
phragm the  thoracic  duct  and  azygos  vein  appear. 


a.  Thoracic  duct. 

&.  Large  azygos  vein. 

c.  Aorta. 

d.  First  lumbar  artery. 

e.  Second  lumbar. 
/.  Third  lumbar. 
g.  Fourth  lumbar. 

h.  Last  intercostal  artery. 
i.  Middle  sacral  artery  giving  a  lum- 
bar branch. 


k.  Common  iliac  artery. 

I.   External  iliac. 

m.  Internal  iliac. 

n.  Ilio-lumbar  branch. 

o.  Gluteal  artery. 

J).  Sciatic  branch. 

r.  Pudic  branch. 

s.  Obturator  branch. 

t.  Visceral  offsets  of  the  iliac. 

V.  Lateral  sacral  branch. 


Lumbar  arteries,  d,  e,  f,  g.  Four  in  number,  they  belong  to  the 
parietal  branches  of  the  aorta;  but  in  this  body  a  fifth  lumbar  springs 
from  the  middle  sacral  artery:  they  are  named  first,  second,  etc.,  like  the 
vertebrae. 

The  vessels  are  directed  backwards  along  the  bodies  of  the  vertebrae 
under  the  crus  of  the  diaphragm  and  the  psoas,  and  each  divides  into  two 
(dorsal  and  abdominal  branches)  between  the  transverse  processes.  The 
dorsal  branches  are  continued  onwards  in  the  direction  of  the  parent 
vessel,  and  supply  the  back,  the  contents  of  the  spinal  canal,  and  the 
vertebrae;  the  abdominal  branches  enter  the  hinder  part  of  the  abdominal 


LIGATURE    OF    THE   INTERNAL    ILIAO    ARTERY.  67 

wall,  and  anastomose  with  the  intercostal  above,  and  with  branches  of 
the  internal  iliac  below. 

The  veins  accompanying  the  lumbar  arteries  open  into  the  inferior 
cava  (Plate  xxxvi.). 

Last  intercostal  artery,  h.  Appearing  below  the  last  rib  with  the  last 
dorsal  nerve,  it  pierces  the  fascia  lumborum.  and  is  distributed  with  its 
nerve  in  the  wall  of  the  abdomen. 

The  internal  iliac  artery,  m,  supplies  the  pelvic  viscera,  and  mam- 
tains  anastomoses  outside  the  pelvis  with  branches  of  the  femoral  trunk. 
It  begins  opposite  the  base  of  the  sacrum  in  the  bifurcation  of  the  com- 
mon iliac  artery,  k,  and  descends  into  the  pelvis  towards  the  great  sacro- 
sciatic  notch,  where  it  divides  into  two  pieces — anterior  and  posterior. 
From  its  extremity  a  partly  obliterated  vessel  (hypogastric)  is  continued 
forwards  on  the  bladder  to  the  umbilicus  in  the  adult  (Plate  xxxviii.,  d), 
but  this  is  open  in  the  foetus  and  forms  the  main  vessel. 

Surrounded  by  much  fat  the  artery  measures  about  one  inch  and  a 
half  in  length,  and  lies  commonly  on  the  lumbo-sacral  cord  and  the  first 
sacral  nerve.  Its  companion  vein  is  ^Dlaced  between  it  and  the  pelvis;  but 
inclines  to  the  outer  part  on  the  right  side. 

Ligature.  The  extent  of  this  as  of  the  other  iliac  arteries  is  subject 
to  great  variations,  but  its  length  commonly  is  from  one  inch  to  one  inch 
and  a  half.  Should  ligature  of  the  vessel  be  required  during  life  the 
length  ought  to  amount  to  one  inch.  And  should  it  be  found  shorter  in 
an  operation,  say  only  half  an  inch,  tying  both  the  iliac  arteries  would  be 
safer  than  putting  a  string  on  the  one  (Quain). 

Branches  of  the  iliac.  These  are  numerous,  aud  are  classified  com- 
monly into  two  sets,  which  come  from  the  two  pieces  (anterior  and  poste- 
terior)  into  which  the  artery  divides;  but  the  origin  of  the  branches 
deviates  greatly  from  the  prescribed  arrangement.  They  may  be 
arranged  in  three  classes,  viz.,  branches  distributed  to  the  parietes  of  the 
pelvis  on  the  inside,  some  exterior  to  the  cavity,  and  others  to  the  viscera. 

The  internal  parietal  set  consists  of  the  ilio-lumbar  and  lateral  sacral 
arteries. 

The  ilio-lumbar  branch,  n,  is  directed  outwards  to  the  iliac  fossa  be- 
neath the  external  iliac  vessels:  there  it  ramifies  in  the  fossa,  some  offsets 
running  on  the  surface  of  the  muscle  to  the  iliac  crest,  and  others  sup- 
plying the  hip-bone.  An  ascending  or  lumbar  branch  anastomoses  with 
the  last  lumbar  artery. 


68  ILLUSTRATIONS    OF   DISSECTIONS. 

The  lateral  sacral  branches  are  two  in  number,  upper  and  lower,  and 
the  upper  is  marked  with  v:  they  run  on  the  side  of  the  sacrum,  supply- 
ing the  pyriformis  and  coccygeus  muscles,  and  send  branches  into  the 
spinal  canal  through  the  anterior  sacral  apertures. 

External  ijarietal  set.  These  are  the  gluteal,  sciatic,  pudic,  and  obtu- 
rator: they  are  furnished  to  parts  outside  the  cavity  of  the  pelvis,  and 
anastomose  with  branches  of  the  femoral  artery.  Only  a  short  piece  of 
each  branch  is  included  in  the  dissection. 

The  gluteal,  o,  the  largest  of  all,  is  directed  backwards  between  the 
sacral  nerves  to  the  upper  part  of  the  great  sacro-sciatic  notch;  it  leaves 
the  pelvis  above  the  pyriformis  muscle,  and  ends  in  the  buttock. 

The  sciatic  artery,  p,  descends  to  the  lower  part  of  the  great  sacro- 
sciatic  notch,  and  passes  from  the  pelvis  below  the  pyriformis  muscle:  it 
ends  in  the  buttock  and  the  back  of  the  thigh. 

The  pudic  branch,  r,  takes  a  downward  course  with  the  preceding, 
and  escapes  from  the  pelvis  between  the  pyriformis  and  coccygeus  mus- 
cles; its  distribution  is  exhibited  in  the  Plates  of  the  Perineum. 

The  oMurator  artery,  s,  runs  forwards  across  thj  pelvic  cavity  with 
the  nerve  of  the  same  name  to  the  sub-pubic  foramen:  external  to  the 
pelvis  it  supplies  the  obturator  muscle  and  the  hip-jomt. 

Visceral  Iranclies.  In  both  sexes  there  are  vesical  and  hemorrhoidal 
arteries;  and  in  the  female  there  are  in  addition  uterine  and  vaginal. 

The  vesical  Iranclies,  t,  three  in  number,  come  from  the  iliac,  and  the 
partly  obliterated  hypogastric  artery  (Plate  xl.),  and  ramify  in  the  upper 
and  lower  regions  of  the  bladder. 

The  middle  licemorrhoidal  artery  arises  most  often  in  common  with 
the  lower  vesical:  it  is  small,  and  is  distributed  in  the  rectum. 

Uterine  and  vaginal  arteries.  These  branches,  which  are  special  to 
the  female,  are  distributed  as  the  names  signify.  The  uterine  is  the 
larger,  and  is  tortuous;  and  the  vaginal  is  generally  an  offset  of  the  mid- 
dle hasmorrhoidal. 

The  large  azygos  vein,  h,  begins  in  a  lumbar  vein,  and  may  communi- 
cate with  the  inferior  cava.  It  enters  the  thorax  through  the  aortic 
opening,  receives  most  of  the  intercostal  veins  of  both  sides,  and  ends  in 
the  vena  cava  superior. 

Tlwracic  duct,  a.  Opposite  the  last  dorsal,  or  the  first  lumbar  verte- 
bra this  tube  begms  in  a  dilatation— receptaculum  chyli,  between  the 
aorta  and  the  right  crus  of  the  diaphragm.     Into  this  dilated  part  three 


SPINAL    NERVES    IN    THE    ABDOMEN. 


69 


or  four  large  lymphatic  vessels  from  the  mesenteric  and  lumbar  glands 
are  received.  It  ascends  then  through  the  thorax,  and  ends  in  the  neck 
by  joining  tlie  left  subclavian  vein. 

The  ilio-vertehral  ligament,  I,  stretches  between  the  transverse  pro- 
cess of  the  last  lanibar  vertebra  and  the  iliac  crest  of  the  hip-bone,  oppo- 
site the  hinder  j)art  of  the  iliac  fossa:  from  the  ujjper  and  posterior 
part  the  quadratus  lumborum  F  takes  origin,  and  from  the  front,  the 
iliacus. 


SPINAL  NERVES  IN  THE  ABDOMEN. 


The  anterior  primary  branches  of  the  lumbar  and  sacral  nerves  are 
united  into  a  large  plexus  along  the  side  of  the  spinal  column.  After 
this  union  several  branches  are  distributed  to  the  limb;  the  crural  offsets 
from  the  upper  part  belong  to  the  front  of  the  limb,  and  those  from  the 
lower  part  of  the  plexus  enter  the  back  of  the  thigh. 


1.  First  lumbar  nerve. 

2.  Second  lumbar. 

3.  Third  lumbar. 

4.  Fourth  lumbar. 

5.  Fifth  lumbar. 

6.  Ilio-hypogastric  branch. 

7.  Ilio-inguinal  branch. 
is.  Genito-crural  branch. 
9.  External  cutaneous. 

10.  Anterior  crural. 


11.  Obturator  nerve. 

12.  First  sacral  nerve. 

13.  Second  sacral. 

14.  Third  sacral. 

15.  Fourth  sacral. 

16.  Superior  gluteal  branch. 

17.  Last  dorsal  nerve. 

23.  Branch  to  lumbo- sacral. 

24.  Lumbo-sacral  cord. 

25.  Sacral  plexus. 


The  lumbar  nerves  are  five  in  number,  and  are  marked  1,  2,  3,  etc. 
They  increase  rapidly  in  size  from  the  first  to  the  last;  and  they  commu- 
nicate with  each  other,  and  with  the  knotted  cord  of  the  sympathetic,  as 
soon  as  they  escape  from  the  intervertebral  foramina.  Small  muscular 
offsets  are  furnished  by  the  nerves  to  the  psoas  and  quadratus. 

Four  of  the  nerves  unite  in  the  lumbar  plexus,  whilst  the  last  or  fifth 
enters  the  sacral  plexus.  Sometimes  too  the  last  dorsal  is  joined  to  the 
first  lumbar  by  a  small  branch  (dorsi-lumbar). 

The  lumbar  plexics  is  formed  by  the  intercommunication  of  the  four 
highest  nerves;  and  it  is  embedded  in  the  large  psoas  muscle.  Below,  it 
is  connected  with  the  sacral  plexus  through  the  lumbo-sacral  cord.     Its 


70  ILLUSTEATIOXS    OF    DISSECTIONS. 

offsets,  six  in  number,  are  furnished  to  the  lower  part  of  the  abdominal 
wall,  to  the  spermatic  cord  coverings,  and  to  the  front  of  the  limb. 

Ilio-hypogastric,  C,  and  ilio-inguinal,  7:  these  two  branches  arise  in 
the  first  nerve,  and  come  into  sight  at  the  top  of  the  jjsoas  muscle. 
Directed  downwards  and  outwards  across  the  quadratus  lumborum  to  the 
iliac  crest,  they  enter  the  wall  of  the  belly,  and  end  in  the  muscles  and 
integuments  (Plate  xxx.,  j).  34).  At  the  iliac  crest  the  nerve,  G,  gives  a 
cutaneous  offset  to  the  buttock. 

Genito-crural,  8.  This  branch  comes  from  the  second  nerve,  and  the 
loop  between  the  first  two.  Piercing  the  fibres  of  the  psoas,  it  descends 
on  the  surface  of  that  muscle  towards  Poupart's  ligament,  and  divides 
into  two. 

The  genital  part,  which  is  cut,  leaves  the  abdomen  with  the  spermatic 
vessels,  and  is  distributed  to  the  cremaster  muscle. 

The  crural  piece  is  continued  below  the  ligament,  and  reaches  the 
teguments  of  the  front  of  the  thigh. 

The  external  cutaneous,  9,  springs  in  the  third  nerve,  and  appears  at 
the  outer  border  of  the  psoas  about  the  middle:  the  nerve  leaves  the  belly 
beneath  Poupart's  ligament  at  the  outer  end,  and  ramifies  in  the  tegu- 
ments of  the  thigh. 

The  anterior  crural  nerve,  10,  is  the  largest  offset  of  the  j^lexus  ;  it 
receives  most  of  the  fourth  nerve,  and  is  joined  by  a  large  fasciculus  from 
the  nerves  above.  Emerging  from  beneath  the  psoas  near  Poupart's 
ligament,  it  lies  in  the  hollow  between  that  muscle  and  the  iliacus. 
Tlie  nerve  escapes  from  the  abdomen  beneath  Poupart's  ligament,  and 
is  supplied  to  the  fore  j^art  of  the  limb. 

In  the  abdomen  it  furnishes  two  or  more  branches  to  the  iliacus  muscle, 
and  a  small  nerve  to  the  coats  of  the  femoral  artery. 

Olturator  nerve,  11.  Beginning  in  the  third  and  fourth  nerves,  it 
comes  into  sight  at  the  pelvic  border  of  the  i^soas.  It  is  then  continued 
across  the  cavity  of  the  pelvis  to  the  sub-pubic  aperture  in  the  upper  part 
of  the  thyroid  foramen,  and  supplies  the  adductor  muscles  of  the  thigh. 

The  lumbosacral  cord,  24,  is  formed  by  the  whole  of  the  fifth  lumbar 
nerve,  and  by  a  fasciculus,  23,  which  is  derived  from  the  fourth  nerve. 
This  large  cord  enters  the  sacral  plexus  in  the  pelvis,  and  serves  as  the 
connecting  nerve  between  this  and  the  lumbar  plexus. 

Before  the  cord  joins  the  first  sacral  nerve  it  gives  origin  to  the  upper 
gluteal  nerve,  16;  this  branch  passes  out  of  the  pelvis  through  the  upper 


KNOTTED    COED    OF    THE    SYMPATHETIC.  71 

part  of  the  great  sacro-sciatic  notch  with  the  gluteal  artery  and  yein, 
and  is  distributed  to  muscles  on  the  back  of  the  pelvis. 

Sacral  nerves.  Five  in  number  like  the  lumbar  nerves,  they  decrease 
in  size  from  above  down.  Four  of  them  issue  from  the  spinal  canal 
through  the  apertures  in  the  front  of  the  sacrum,  and  the  fifth  or  last 
comes  between  the  sacrum  and  the  coccyx.  The  three  highest,  and  part 
of  the  fourth,  enter  the  sacral  plexus;  but  the  rest  of  the  fourth  joins 
the  fifth  nerve,  and  terminates  in  muscular  and  visceral  branches.  The 
fifth  sacral  joins  the  coccygeal  nerve,  and  ends  on  the  back  of  the  coccyx. 

The  sacral  plexus,  25,  is  formed  chiefly  by  the  union  of  the  three 
upi3er  sacral  nerves  with  part  of  the  fourth,  as  before  said;  and  it  is 
further  joined  by  the  large  lumbo-sacral  cord,  24,  from  above.  Its  com- 
ponent nerves  blend  together  in  a  flat  band,  which  rests  on  the  pyriformis 
muscle . 

Its  branches  are  numerous: — Some  belong  to  the  external  rotator 
muscles,  and  will  be  dissected  with  the  buttock;  others  are  prolonged  to 
the  back  of  the  limb;  and  one  is  distributed  to  the  perineum. 

Last  dorsal  nerve,  1.7.  This  lies  below  the  last  rib,  and  appears  in  the 
abdomen  after  passing  through  or  beneath  the  external  arched  ligament, 
with  its  accompanying  vessels.  After  a  distance  of  about  three  inches, 
it  pierces  the  posterior  tendon  of  the  transversalis  muscle  (fascia  lum- 
borum),  and  terminates  in  the  abdominal  wall.  A  separate  small  abdom- 
inal branch  arises  from  the  nerve  before  this  leaves  the  abdomen. 


KNOTTED   CORD   OF  THE  SYMPATHETIC. 

In  the  abdomen  the  sympathetic  consists  of  plexuses  in  front  of  the 
vertebral  column,  for  the  supply  of  the  viscera;  and  of  two  gangliated 
cords,  one  on  each  side  of  the  spine,  which  join  the  different  spinal 
nerves.  As  the  viscera  have  been  removed  from  the  abdomen  only  the 
knotted  cords  remain. 


18.  Great  splanchnic  nerve. 

19.  Small  splanchnic. 

20.  Smallest  splanchnic. 


21.  Lumbar  part  of  the  gangliated 

cord. 

22,  Sacral  part  of  the  cord. 


The  lumharpart  of  the  gangliated  cord,  21,  lies  along  the  inner  border 
of  the  psoas  muscle,  and  is  covered  on  the  right  side  by  the  vena  cava 


72  ILLUSTRATIONS   OF   DISSECTIONS. 

inferior.  A  ganglion  exists,  for  the  most  part,  opposite  each,  vertebra; 
and  from  it  offsets  are  prolonged  internally  and  externally. 

The  external  hrdnches,  two  in  number  from  each  ganglion,  join  gen- 
erally two  spinal  nerves. 

The  internal  irajiches  are  directed  over  the  aorta,  and  terminate  in 
the  large  visceral  plexuses. 

The  sacral  2^ art  of  the  cord,  22,  rests  on  the  front  of  the  sacrum  in- 
ternal to  the  row  of  apertures.  Below,  the  cords  of  opposite  sides  are 
connected  by  a  loop  in  front  of  the  coccyx,  on  which  there  is  situate  a 
single  median  ganglion — the  "ganglion  impar."  The  number  of  the 
ganglia  is  oftentimes  less  than  that  of  the  vertebrae;  and  those  bodies  are 
smaller  in  the  pelvis  than  elsewhere.  External  and  internal  offsets  arc 
given  from  these  as  from  the  lumbar  ganglia. 

External  branches,  two  in  number,  enter  either  one  or  two  sjDinal 
nerves. 

Internal  or  visceral  branches,  small  in  size,  are  continued  from  the 
first  two  ganglia  to  the  nerve-centre  in  front  of  the  sacrum,  called  the 
hypogastric  plexus;  the  branches  from  the  remaining  ganglia  ramify  on 
the  front  of  the  sacrum,  and  form  a  plexus  on  the  middle  sacral  artery. 

Splanchnic  nerves.  These  are  three  in  number  on  each  side,  and 
take  origin  in  the  ganglia  of  the  knotted  cord  of  the  sympathetic  in  the 
thorax.  They  are  named  large,  small,  and  smallest,  and  pierce  the  fibres 
of  the  crus  of  the  diaphragm. 

The  large  splanchnic,  10,  ends  in  one  of  the  ganglia  (semilunar), 
forming  part  of  the  solar  plexus  in  the  abdomen. 

The  small  splanchnic,  19,  terminates  near  the  preceding  in  the  lateral 
part  of  the  solar  plexus. 

The  smallest  splanchnic,  or  renal  nerve,  20,  throws  itself  chiefly  into 
the  plexus  for  the  kidney,  and  joins  the  solar  plexus. 


PLATE  XXXVIi 


'■V^JS' 


MUSCLES   CLOSING    THE    PELVIC    OUTLET. 


73 


DESCRIPTION  OF  PLATE  XJXVIII. 


FiEST  view  of  the  dissection  of  the  pelvis,  to  illustrate  the  anatomy 
of  the  muscles  closing  the  pelvic  outlet. 

For  this  side-view  the  left  limb  was  removed  by  sawing  through  the 
hip-bone  near  the  symphysis  pubis  in  front,  and  near  the  articulation 
with  the  sacrum  behind,  the  muscles  of  the  abdominal  wall  having  been 
previously  divided  by  a  cut  from  the  one  sawn  part  of  the  pelvis  to  the 
other.  After  forcibly  abducting  the  hip-bone  the  pelvic  fascia  was  de- 
tached, and  the  ischial  spine  was  cut  off  with  a  bone  forceps,  and  thrown 
down  with  its  muscles. 

A  large  quantity  of  fat  will  need  removal  from  the  perinseal  surface 
of  the  levator  ani;  from  the  pudic  artery  and  nerve  lying  against  that 
muscle;  from  the  viscera  in  the  pelvis;  and  from  the  branches  of  the  in- 
ternal iliac  artery  and  the  sacral  plexus. 

MUSCLES   CLOSING  THE  PELVIC   OUTLET. 

Three  muscles,  viz.,  levator  ani,  coccygeus,  and  pyriformis,  close  on 
each  side  the  elongated  interval  between  the  ilio-sacral  articulation  and 
the  symphysis  pubis.  Other  muscles  of  the  abdominal  wall,  loins,  and 
buttock,  are  shown  cut  through  in  the  Figure. 


A.  External  oblique  muscle. 

B.  Internal  oblique,  and.  the  trans- 

versals. 

C.  Psoas  magnus  muscle. 

D.  Iliacus  muscle. 

E.  The  i-ectum  or  large  intestine. 

F.  Bag  of  the  peritoneum. 

G.  Vas  deferens  of  the  testis. 
H.  Ui-inary  bladder. 

I.  Spermatic  cord. 

J.  Ureter  of  the  kidney. 


K.  Cms  penis,  cut  through. 
L.  Anterior  layer     )      of  triangular 
N.  Posterior  layer    f       ligament. 
O.  Ejaculator  uringe  muscle. 
P.  Levator  ani  muscle. 
Q.  Ischial  spine,  cut  off. 
R.  Coccygeus  muscle. 
S.  Sphincter  ani  extemus. 
T.  Gluteus  maximus  muscle. 
V.  Pyriformis  muscle. 
W.  Hip-bone,  6ut. 


74  ILLUSTRATIONS    OF    DISSECTIONS. 

The  iiyriformis  muscle,  V,  arises  by  fleshy  slips  from  the  bodies  of 
three  sacral  vertebrae  (the  first  and  last  bones  being  free);  from  the  lat- 
eral mass  of  the  sacrum  outside  the  anterior  foramina;  and  from  the 
upper  part  of  the  hinder  border  of  the  hip-bone,  and  the  sacro-sciatic 
ligament.  Leaving  tlie  pelvis  by  the  great  sacro-sciatic  notch,  it  crosses 
the  back  of  the  hip-joint  to  be  inserted  into  the  great  trochanter.  See 
Plate  of  the  Buttock. 

In  the  pelvis  the  muscle  lies  beneath  the  sacral  plexus,  and  some 
branches  of  the  internal  iliac  artery;  and  on  the  left  side  the  rectum  rests 
on  it.  As  it  passes  through  the  great  sacro-sciatic  notch  it  divides  that 
space  into  two.     In  contact  with  the  lower  border  is  the  coccygeus. 

The  coccygeus  muscle,  E,  thin  and  triangular  in  shape,  arises  from 
the  upper  edge  and  the  point  of  the  ischial  spine,  Q,  of  the  hip-bone;  and 
it  is  inserted  by  a  widened  part  into  the  front  of  the  coccyx  near  the 
■edge,  and  into  the  last  piece  of  the  sacrum. 

Intermediate  in  position  between  the  levator  ani  and  the  pyriformis, 
the  muscle  reaches  by  its  lower  edge  the  levator,  and  is  separated  from 
the  pyriformis  by  the  pubic  and  sciatic  vessels  and  nerves.  The  pelvic 
surface  touches  the  rectum  on  the  left  side,  and  the  perineal  surface 
blends  with  the  small  sacro-sciatic  ligament  which  partly  conceals  it:  the 
muscle  is  crossed  posteriorly  by  the  pudic  nerve. 

The  muscles  of  opposite  sides  support  the  pelvic  viscera  and  the 
■coccyx;  and  shortening  by  the  contraction  of  the  fibres,  they  will  draw 
iorwards  the  coccyx  after  the  bone  has  been  forced  backwards. 

Levator  am,  P.  The  insertion  of  the  muscle  is  shown  in  Plate  xxx., 
:and  the  origin  appears  in  this  side-view  of  the  pelvis. 

It  arises  in  front  from  the  back  of  the  pubes  just  above  the  obturator 
internus,  lower  down  from  the  fascia  covering  the  obturator  muscle,  and, 
still  lower,  from  the  back  of  the  triangular  ligament,  IST;  behind,  from 
the  lower  border  of  the  ischial  spine,  Q;  and  between  those  osseous  at- 
tachments, from  the  under  surface  of  the  recto-vesical  fascia.  Its  fibres 
are  inclined  down  and  back,  and  have  the  undermentioned  insertion; — 
the  most  anterior  unite  below  the  triangular  ligament  with  the  muscle  of 
the  other  side  in  the  central  point  of  the  j)erin8eum;  others  course  back- 
wards over  the  side  of  the  gut,  some  joining  the  muscular  coat  of  the  in- 
testine, to  meet  the  fibres  of  the  opposite  muscle  in  a  tendinous  line 
between  the  gut  and  the  coccyx;  and  the  posterior  fibres  end  on  the  lower 
part  of  the  coccyx. 


INTERNAL    ILIAC    ARTERY.  75 

By  their  position  in  the  pelvic  outlet  the  muscles  form  a  fleshy  dia- 
phragm, which  is  convex  to  the  perinasum  and  is  pierced  by  the  rectum. 
The  outer  surface  looks  to  the  wall  of  the  pelvis  and  the  ischio-rectal 
fossa;  and  the  inner,  to  the  bladder  and  urethra,  and  the  rectum.  The 
anterior  border  lies  against  the  urethral  tube  in  the  male,  and  the  urethra 
and  vagina  in  the  female;  whilst  the  interval  between  the  muscles  of  op- 
posite sides  is  closed  by  the  triangular  ligament  of  the  urethra. 

When  the  levator  ani  contracts  it  raises  the  rectum;  and  it  will  restore 
to  the  natural  position  the  lovver  end  of  the  intestine  which  has  been  pro- 
truded, and  everted  in  the  passing  of  the  fgeces.  It  will  also  compress  the 
lower  part  of  the  bladder,  and  the  generative  organs  lying  below  and  in 
front  of  that  viscus.  And  as  the  muscles  of  opposite  sides  unite  below 
the  urethral  tube  in  the  male,  and  the  vagina  in  the  female,  they  will  be 
able  to  constrict  those  passages.  By  means  of  the  fibres  attached  to  the 
coccyx  the  muscles  will  raise  that  bone  with  the  aid  of  the  coccygeus. 

The  triangular  ligament  of  the  urethra  is  described  in  p.  22.  In 
this  Figure  the  two  layers  are  represented  as  they  appear  after  the  re- 
moval of  the  bone  to  which  ihey  are  attached  laterally.  The  two  strata 
of  which  it  consists  are  farther  apart'in  the  middle  line  than  at  the  sides, 
and  between  them  lie  muscles,  vessels,  and  nerves.  Inferiorly,  the  layers 
blend  together;  and  from  the  lower  edge  a  thin  fascia  is  prolonged  over 
the  levator  ani  muscle  in  the  ischio-rectal  fossa.  In  this  view  the  pos- 
terior layer  is  seen  to  be  pierced  by  the  dorsal  artery  and  nerve  of  the 
pudic;  and  to  give  attachment  to  the  levator  ani,  P. 

INTERNAL  ILIAC   ARTERY. 

Visceral  branches,  and  the  obliterated  hypogastric,  are  continued  for- 
wards from  the  end  of  the  internal  iliac;  and  these,  with  the  pudic  ar- 
tery, are  the  chief  vessels  in  the  Figure.  The  other  arteries,  which  are 
cut  through,  do  not  require  further  notice  than  that  contained  in  the 
table  of  reference. 


a.  Common  iliac  artery. 
h.  Comraon  iliac  vein. 

c.  Superior  vesical  artery. 

d.  Oblitei'ated  hypogastric, 

e.  Middle  vesical  artery. 
/,  Inferior  vesical  artery. 
g.  Pudic  artery. 

h.  Inferior  hemorrhoidal  branch. 


i.  Superficial  perinaeal  branch. 

^-     ] 

V  Dorsal  artery  of  the  penis. 

I.  Artery  of  the  bulb. 
n.  Spermatic  artery. 
o.  Spermatic  veins. 
p.  Sciatic  artery,  cut. 
r.  Branch  of  the  sciatic. 


76  ILLU8TEATION8    OF   DISSECTIONS. 

Obliterated  hypogastric.  In  the  foetus  the  artery  in  the  place  of  the 
internal  iliac  is  continued  through  the  umbilicus  to  the  placenta.  This 
vessel  is  called  hypogastric  as  it  lies  by  the  side  of  the  bladder  and  within 
the  belly,  and  umbilical  outside  the  cavity.  After  birth  that  artery  is 
obliterated,  and  the  cord  above  noticed  remains  in  its  place. 

This  cord,  d,  is  jDlaced  in  tho  r^dult  on  the  lateral  part  of  the  bladder 
as  far  as  the  apex,  and  then  against  the  abdominal  wall  as  high  as  the 
umbilicus.  By  its  side  lies  a  small  artery  which  furnishes  vesical 
offsets. 

Vesical  arteries.  Two  or  three  in  number,  they  spring  from  the  fore 
part  of  the  internal  iliac  trunk:  the  upper  and  middle,  v  c^nd  e,  supply 
the  greater  part  of  the  bladder,  whilst  the  lower,  f,  is  distributed  to  the 
base,  and  to  the  generative  parts  below. 

Pudic  artery,  g.  In  the  views  of  the  perinseum  this  vessel  has  been 
exhibited  in  parts,  but  in  this  side-view  it  is  laid  bare  from  the  beginning 
nearly  to  the  end.  It  leaves  the  pelvis  through  the  lower  part  of  the 
great  sacro-sciatic  notch,  and  winding  over  the  bark  of  the  ischial  spine, 
appears  in  the  ischio-rectal  hollow  of  the  pefinseum  by  passing  through 
the  small  sacro-sciatic  notch.  Entering  next  between  the  layers  of  the 
triangular  ligament  by  perforating  the  posterior  piece,  IST,  near  the  base, 
it  finally  ijierces  the  anterior  layer  near  the  symphysis  pubis  (Plate  xxx. ), 
and  ends  in  the  penis. 

Its  named  offsets  are  furnished  chiefly  to  the  lower  end  of  the  rectum, 
to  the  perineum  and  scrotum,  and  to  the  urethra  and  the  penis:  they 
are  numerous,  and  arise  from  behind  forwards  as  here  stated: — Inferior 
hsemorrhoidal,  h,  one  or  two  in  number;  superficial  perinseal,  i;  artery  of 
the  bulb,  I;  dorsal  artery  of  the  penis,  j;  and  muscular  to  the  levator  ani 
and  the  perinseal  muscles.  Eor  the  detailed  description  of  these  branches, 
see  the  Peringeum. 

The  sciatic  artery,  p,  which  is  seen  to  descend  through  the  pelvis  in 
Plate  xxxvi.,  escapes  from  that  cavity  below  the  pyriformis,  V,  lying 
between  this  and  the  coccygeus,  R. 


PUDIC  NERVE  AND  BRANCHES. 

The  distribution  of  this  nerve  is  displayed  in  the  Plates  of  the  Peri- 
naBum,  but  its  origin,  general  course,  and  branching,  apjoear  in  this 
view. 


PLATE  XXXIX. 


\ 


RECTO- VESICAL    FASCIA. 


77 


1.  Sacral  plexus. 

2.  Dorsal  nerve  of  the  penis. 

3.  Perinjeal  nerve. 

4.  Inferior  ligemorrhoidal  branch. 


5.  Superficial  perinasal  branches. 

6.  Brancli  to  ejaculator  urinse. 

7.  Branch  to  constrictor  urethras. 


The  pudic  nerve  arises  in  the  sacral  plexus  as  one  or  two  pieces,  and 
has  the  same  general  course  and  distribution  as  the  artery  of  the  same 
name.  "Where  it  begins  as  a  single  trunk  the  parts,  2  and  3,  are  blended 
as  far  as  the  ischial  spine,  Q;  but  at  this  point  they  separate,  one,  infe- 
rior, reaching  the  perin^eum,  and  the  other,  superior  in  position,  being 
furnished  to  the  penis. 

The  2}erinceal  branch  is  directed  forwards  to  the  scrotum  in  which  it 
ends;  its  offsets  are  these: — one  or  two  inferior  haemorrhoidal  branches,  4, 
to  the  muscles  and  integuments  of  the  lower  end  of  the  rectum:  two 
superficial  perinaeal  branches,  5  (anterior  and  posterior),  to  the  integ- 
uments of  the  scrotum;  and  branches  to  the  muscles,  and  the  part  of  the 
urethra  in  the  perineum,  of  which  two,  6  and  7,  are  shown. 

The  dorsal  nerve  of  the  penis,  2,  ascends  along  the  side  of  the  pelvis 
and  the  internal-  obturator  muscle  to  the  back  of  the  triangular  ligament; 
and  takes  its  place  between  the  layers  of  that  membrane  by  penetrating 
the  posterior  layer  higher  than  the  dorsal  artery  of  the  penis.  In  com- 
pany with  the  artery  of  the  same  name  it  ascends  near  to  the  symphysis 
puhis,  perforates  the  anterior  layer  of  the  ligament,  and  is  distributed  to 
the  body  and  the  integuments  of  the  penis. 


DESCRIPTIOX  OF  PLATE  XXXIX. 


The  arrangement  of  the  recto-vesical  fascia  is  set  forth  in  this  seconc 
view  of  the  dissection  of  the  pelvis. 

After  dividing  the  levator  ani  near  its  origin,  and  throwing  down  that 
muscle,  the  recto-vesical  fascia  will  become  apparent.  To  demonstrate 
the  existence  of  sheaths  of  the  membrane  on  the  prostate  and  the  rec- 
tum, incisions  may  be  made  in  a  longitudinal  direction  into  the  fascia  on 
those  viscera,  as  in  the  Eigure. 


78  ILLUSTKATI0N8    OF    DISSECTIONS. 


RECTO-VESICAL  FASCIA. 


This  membrane  is  attached  to  the  viscera,  assisting  to  support  them, 
and  forms  a  partition  between  the  pelvis  and  the  perinaeum.  The  same 
letters  of  reference  for  the  same  parts  are  used  in  this  and  the  preceding 
Figure. 


A.  Rectovesical  fascia. 

B.  Line  of  attachment  to  the  viscera. 

C.  Sheath  on  the  prostate. 

D.  Sheath  for  the  rectum. 

E.  Upper  part  of  the  rectum.. 

F.  Bag  of  the  peritoneum. 

G.  Vas  deferens  of  the  testis. 
H.  Urinary  bladder. 

I.    Spermatic  cord. 


J.    Ureter  from  the  kidney. 

K.  Crus  penis,  cut. 

L.  Prostate. 

N.  Triangular  ligament. 

O.  Ejaculator  urinse. 

P.  Levator  ani,  thrown  down. 

Q.  Ischial  spine,  cut  off. 

R.  Coccygeus  muscle. 

S.    Rectum,  lower  part. 


The  redo-vesical  fascia,  A,  gives  origin  in  part  to  the  levator  ani  mus- 
cle, and  partly  joins  the  pelvic  fascia.  Before  the  hip-bone  is  removed 
the  fascia  may  be  seen  to  be  attached  to  the  wall  of  the  pelvis  above  the 
origin  of  the  levator  ani,  and  to  be  directed  inwards  obliquely  on  that 
muscle  to  the  viscera,  where  it  meets  with  a  similar  piece  on  the  opposite 
side,  and  forms  a  septum  between  the  cavity  of  the  pelvis  and  the  peri- 
naeum. This  septum  is  rather  convex  below,  and  is  pierced  by  the  lower 
part  of  the  bladder  and  the  rectum,  so  that  the  viscera  are  partly  within 
the  cavity  of  the  abdomen,  and  partly  outside  the  flooring  or  membran- 
ous boundary  of  that  cavity.  Though  the  viscera  pass  through  the  fascia 
there  is  not  any  passage  leading  from  the  pelvic  cavity,  for  the  margins 
of  the  apertures  for  their  transmission  are  inseparably  united  to  the  parts 
transmitted.  From  the  under  or  perinseal  surface  of  the  fascia  are  fur- 
nished two  prolongations,  like  the  fingers  of  a  glove,  which  form  sheaths 
for  the  prostate  and  the  rectum. 

As  the  fascia  suspends  the  bladder,  it  forms  the  true  ligaments  of  this 
viscus  on  each  side,  and  in  front.     These  will  be  noticed  below. 

The  sheath  of  the  prostate,  C,  derived  from  the  recto-vesical  fascia,  as 
above  said,  blends  at  the  front  of  that  body  with  the  posterior  layer,  N, 
of  the  triangular  ligament.     It  gives  a  complete,  though  not  very  dense 


.   RECTO- VESICAL    FASCIA.  T9 

covering,  and  is  separated  from  the  prostate  by  a  plexus  of  veins,  and  by 
some  small  arteries. 

Sheath  of  the  rectum.  This  incases  about  the  lower  three  inches  of 
the  gut,  and  is  continued  to  the  anus  Avhere  it  gradually  ends.  It  is 
thicker  than  the  tube  on  the  prostate,  and  is  separated  from  the  intestine 
by  fat,  and  by  the  upper  hgemorrhoidal  vessels. 

Ligaments  of  the  Uadder.  The  part  of  the  fascia  intervening  between 
the  wall  of  the  pelvis  and  the  bladder  constitutes,  as  before  said,  the  true 
ligaments  of  that  viscus:  they  are  two  in  number  on  each  side,  anterior 
and  lateral,  but  there  is  not  any  slit  or  division  between  them. 

The  anterior,  T,  is  a  narrow  prominent  band,  which  reaches  from  the 
back  of  the  pubes  to  the  sheath  of  the  prostate  and  the  neck  of  the  blad- 
der. It  contains  a  bundle  of  muscular  fibres  derived  from  the  external 
or  longitudinal  layer  of  the  urinary  bladder.  A  hollow  exists  between 
the  ligaments  of  opposite  sides. 

The  lateral  ligament  is  the  wide  expanded  part  of  the  fascia,  A,  which 
is  attached  to  the  neck  and  side  of  the  bladder  above  the  vesicula  semi- 
nalis,  along  the  line,  B.  From  its  insertion  a  piece  is  continued  under 
the  bladder  to  incase,  with  a  like  piece  from  the  opposite  side,  the  vesicula 
seminalis  in  a  sheath. 

Ligament  of  the  rectum  ?  No  name  has  been  given  to  the  part  of  the 
fascia  which  is  attached  to  the  gut;  but  from  the  ischial  spine  the  mem- 
brane is  continued  to  the  intestine,  and  this  part  might  be  called  the 
lateral  ligament  of  the  rectum,  from  its  supporting  that  viscus. 

From  the  arrangement  of  the  recto-vesical  fascia  on  the  viscera  it  ap- 
pears that  the  prostate,  and  the  lower  part  of  the  rectum,  lie  below  the 
septum  or  the  membranous  flooring  of  the  abdomen,  and  may  be  reached 
from  the  peringeum  without  entering  the  cavity  of  the  pelvis.  About  a 
finger's  length  of  the  intestine  may  be  cut  without  passing  the  limits  of 
the  fascia;  and  all  the  prostate  may  be  cut  through  in  a  direction  down- 
wards and  backwards  without  injuring  the  septum.  The  reflection  of  the 
fascia  with  respect  to  the  prostate  demonstrates  how  division  of  this  body 
can  be  made  for  the  extraction  of  a  stone  from  the  bladder  without  enter- 
ing the  pelvis;  and  its  disposition  on  the  rectum  will  explain  how  the 
intestine  may  be  slit  in  the  operation  for  flstula  in  ano  without  serious 
eonsequences  ensuing. 

The  attachment  of  the  fascia  to  the  side  of  the  bladder  indicates  in 
what  direction  a  cut  is  to  be  made  in  that  viscus  for  the  extraction  of  a 


80 


ILLUSTRATIONS    OF    DISSECTIONS. 


calculus  ill  the  adult,  which  is  larger  than  the  prostate,  or  even  of  a  stone 
of  moderate  size  in  the  child.  An  incision  carried  downwards  and  back- 
wards below  the  attachment,  B,  of  the  fascia,  but  parallod  and  close  to  it, 
would  divide  the  viscus  along  the  upper  edge  of  the  vesicula  seminalis,  and 
would  be  situate  below  the  ::^C'ptal  piece,  A,  and  therefore  below  the  cavity 
of  the  abdomen.  In  the  case  of  such  a  cut  being  practised  the  urine 
would  flow  down  to  the  peringeum,  because  the  barrier  presented  by  the 
septal  i^art  of  the  fascia  would  stop  its  progress  in  the  opposite  direction. 
Should,  however,  an  incision  be  made  upwards,  in  a  direction  towards 
the  apex  of  the  bladder,  the  knife  would  divide  the  septal  jjiece  of  the 
fascia,  and  oj)en  up  the  cavity  of  the  i^elvis. 


Vessels  and  nerves.  Some  of  the  arteries  to  the  viscera,  and  a  part 
of  the  sacral  plexus,  are  shown  in  this  and  the  preceding  Plate;  but  they 
will  be  noticed  in  the  description  of  the  next  Plate.  The  letters  of  refer- 
ence by  which  they  are  marked  are  the  same,  for  the  most  part,  in  all 
the  Figures  of  the  side-view  of  the  pelvis. 


a.  Common  iliac  artery. 

6.  Common  iliac  vein. 

d.  Obliterated  hypogastric. 

/.   Inferior  vesical. 

g.  Branchesof  upper  hgemorrhoidal. 

7i.  Artery  to  levator  ani,  cut. 


i.    Dorsal  artery  of  the  penis. 

I,   Prostatic  artery. 

n.  Spermatic  artery. 

o.  Spermatic  veins. 

•p.  Sciatic  artery. 

f  f  Nerve  to  levator  ani,  cut  through. 


DESCRIPTION  OF  PLATE  XL. 


The  connections  of  the  viscera  of  the  male  are  given  in  this  last  side- 
view  of  the  pelvis. 

On  removing  the  pelvic  fascia,  the  areolar  tissue,  and  the  fat,  the  vis- 
cera will  appear  as  they  are  represented  in  the  Plate.  The  bag  of  the 
peritoneum  may  be  left  unopened. 


CONNECTIONS  OF  THE  VISCERA. 

The  two  large  viscera  in  the  male  pelvis  are  the  urinary  bladder  and 
the  rectum.     And  connected  with  the  under  surface  of  the  bladder  are 


PLATE  XL 


^•■^■ 


CONNECTIONS    OF   THE   RECTUM. 


81 


some  accessory  parts  of  the  generative  apparatus,  viz.,  tlie  vesiculie  semi- 
nales  with  the  vasa  deferentia,  and  the  prostate. 


A.  Anterior  true  ligament  of  the 

bladder. 

B.  Vesicula  seminalis. 

C.  Lower  part     ") 

D.  Middle  part    J-  of  the  rectum. 

E.  Upper  part     J 

F.  Pouch  of  the  peritoneum. 

G.  Vas  deferens. 


H.  Urinary  bladder. 

J.   Ureter. 

K.  Crus  penis,  cut. 

L.  Prostate. 

N.  Triangular  ligament. 

P.  Levator  ani,  cut. 

R.  Coccygeus. 

S.  Sphincter  ani  externus. 


The  rectum,  or  the  lower  part  of  the  large  intestine,  begins  opposite 
the  articulation  of  the  left  hip-bone  with  the  sacrum,  and  ends  at  the 
anus.  Between  those  points  it  takes  a  bent  course  behind  and  below  the 
bladder,  and  lies  in  the  curve  of  the  sacrum  and  coccyx.  It  measures 
about  eight  inches  in  length,  and  is  divided  into  three  parts. 

The  upper  part,  E,  extends  to  the  third  piece  of  the  sacrum;  it  is 
inclined  inwards  to  the  mid-line  of  that  bone,  and  it  is  surrounded  by 
the  peritoneum  which  attaches  it  to  the  pelvic  wall  by  a  fold — the  meso- 
rectum.  Branches  of  the  left  internal  iliac  artery,  and  the  left  ureter, 
are  directed  forwards  by  the  side  of  the  gut. 

The  middle  portion,  D,  reaches  to  the  end  of  the  coccyx  and  the 
coccygeus  muscle.  It  is  about  three  inches  long;  and  it  is  invested  by  the 
peritoneal  pouch,  F,  which  tapering  gradually  to  a  point,  covers  the 
sides  and  front  of  the  intestine  above,  but  only  the  fore  part  below. 
Resting  behind  on  the  sacrum  and  coccyx,  it  touches  in  front  the  under 
part  of  the  bladder,  with  the  vesiculse  seminales  and  the  vasa  deferentia. 
On  each  side  descends  the  coccygeus,  R. 

The  third  piece,  C,  intervenes  between  the  tip  of  the  coccyx,  and  the 
anus;  it  measures  about  one  inch  and  a  half,  and  is  curved  backwards 
somewhat.  It  is  destitute  of  serous  membrane.  Above,  are  the  fore  part 
of  the  prostate,  and  the  membranous  and  bulbous  parts  of  the  urethra. 
It  is  incased  by  muscles; — the  levatores  ani  of  opposite  sides  covering  and 
supporting  it  laterally  and  behind,  and  the  external  sphincter  surround- 
ing it  at  the  anus.  Its  cavity  is  narrowed  at  the  orifice  on  the  surface; 
but  above  that  point  is  a  dilatation,  which  is  greatly  enlarged  in  old  men 
so  as  to  rise  upwards  on  the  sides  of  the  prostate,  and  in  which  the  fseces 

accumulate. 
6 


82  ILLUSTRATIONS.  OF    DISSECTIONS. 

By  tlie  introduction  of  tlie  finger  into  the  rectum,  the  size  and  con- 
dition of  the  prostate  may  be  ascertained;  and  by  the  same  means  assist- 
ance may  be  given  sometimes  in  the  recognition  of  a  calculus  in  tlie 
bladder,  for  the  finger  can  raise  and  bring  within  reach  of  the  sound  a 
stone  that  has  fallen  into  the  hollow  of  the  bladder  behind  the  prostate. 

In  the  operation  of  j^uncturing  the  bladder  through  the  rectum  for 
retention  of  urine,  a  bent  canula  with  a  trocar  is  passed  into  the  gut, 
and  is  guided  by  the  fore  finger  to  the  under  part  of  the  bladder  which 
is  to  be  j)unctured,  viz.,  the  base  between  the  vesiculge  seminales,  and 
behind  the  prostate.  But  the  instrument  should  not  be  introduced 
farther  than  three  inches  from  the  anus,  lest  the  pouch,  F,  of  the  peri- 
toneum should  be  injured. 

As  the  arteries  j,  h,  I,  etc. ,  which  are  directed  longitudinally  on  the 
exterior,  pierce  the  intestine'  and  take  a  straight  course  inside  to  the  anus, 
they  will  be  best  avoided  in  an  operation  by  cutting  j)arallel  to  them. 
The  arrangement  of  these  arteries  lower  down  in  the  gut  will  be  referred 
to  afterwards. 

The  urinary  Madder,  H,  receives  the  urine  conveyed  by  the  ureters, 
and  assists  through  the  contraction  of  its  muscular  wall  in  the  expulsion 
of  that  fluid  from  the  body.  It  is  placed  at  the  front  of  the  pelvis,  above 
the  rectum,  and  is  partly  surrounded  by  peritoneum,  which  helps  to 
retain  it  in  situ. 

Its  form  is  determined  by  its  degree  of  distention.  When  empty  it 
is  flattened,  and  is  triangular  in  shape;  but  as  it  becomes  distended  it 
assumes  a  conical  form,  Avith  the  apex  towards  the  abdominal  wall  and 
the  base  to  the  rectum.  Its  height  in  the  abdomen  varies  with  the 
degree  of  dilatation;  for  it  lies  below  the  brim  of  the  pelvis  in  the  con- 
tracted state,  but  as  it  expands  it  rises  above  the  pelvis  against  the  abdom- 
inal wall;  and  in  extreme  distention  it  is  curved  forwards  over  the  pubes 
by  the  resistance  opposed  by  the  small  intestines  to  its  ascent. 

When  moderately  dilated  it  measures  about  five  inches  in  length,  and 
three  in  diameter,  and  holds  about  a  pint;  but  it  is  larger  in  the  female 
than  the  male.  Parts  of  it  have  received  the  following  designations: — 
The  upper  end  is  named  apex,  and  the  lower,  the  base;  the  intervening 
portion  is  the  body;  and  the  term  neck  is  given  to  the  part  surrounded  by 
the  prostate. 

Connections  of  the  Madder: — The  apex  touches  the  pubes,  or  the 
abdominal  wall  according  to  the  distention.     From  it  three  cords  are 


CONNECTIONS    OF    THE    BLADDER.  83 

continued  to  the  umbilicus,  viz.,  the  obliterated  hypogastric  artery  on 
each  side,  and  the  urachus  in  the  middle.  Behind  the  cords  the  bladder 
is  covered  by  the  peritoneum,  but  is  free  from  that  membrane  in  front 
of  them. 

The  base  or  fundus  rests  on  the  middle  piece  of  the  rectum  without 
the  intervention  of  peritoneum.  In  contact  with  it  on  each  side  is  the 
vesicula  seminalis  with  the  vas  deferens;  and  the  part  between  those 
bodies  is  called  the  triangular  space  of  the  bladder.  The  size  of  the  base 
and  its  shape  depend  upon  the  distention;  for  as  the  bladder  increases 
in  size  it  projects  towards  the  rectum,  and  forms  a  pouch  below  the 
level  of  the  cervix  and  the  canal  of  the  urethra,  into  which  a  calculus 
will  subside. 

The  body  of  the  viscus  touches  in  front  the  wall  of  the  pelvis,  and 
is  free  from  peritoneum;  and  when  the  bladder  is  distended  it  rises 
above  the  pelvis,  and  can  be  reached  without  injury  to  the  serous  mem- 
brane, by  an  incision  through  the  lower  part  of  the  abdominal  wall. 
Behind,  it  is  covered  by  the  peritoneum,  and  is  in  contact  more  or  less 
with  the  small  intestines,  which  descend  into  the  pelvis  in  some  bodies. 
Laterally  the  obliterated  hypogastric  artery  ascends  along  the  viscus;  and 
descending  behind  this  is  the  vas  deferens,  which  passes  internal  to  the 
ureter  and  the  vesicula  seminalis.  Nearer  the  fundus  the  ureter  jnerces 
the  muscular  wall.  All  the  side  behind  the  obliterated  hypogastric  is 
clothed  by  the  peritoneum,  whilst  all  in  front  of  it  is  devoid  of  that  layer; 
so  that  the  cord  of  the  obliterated  vessel  lies  along  the  line  of  reflection 
of  the  serous  membrane. 

The  neck  or  cervix  is  the  narrowed  part  of  the  bladder  which  is  sur- 
rounded by  the  prostate;  and  from  it  the  urethra  or  the  excretory  canal 
of  the  urine  is  continued.  In  the  contracted  state  of  the  viscus  it  is  the 
lowest  part  of  the  cavity,  but  in  distention  it  is  placed  considerably  above 
the  fundus. 

The  ureter,  J,  brings  the  urine  from  the  kidney  to  the  bladder. 
Crossing  the  common  iliac  vessels,  it  is  continued  through  the  j^elvis  to 
the  bladder;  and  it  pierces  this,  below,  at  the  lateral  aspect,  and  about 
one  inch  and  a  half  from  the  prostate.  In  the  pelvic  cavity  it  forms  an 
arch  below  that  of  the  obliterated  hypogastric  artery. 

Ligaments  of  the  hladder.  This  viscus  is  retained  in  place  partly  by 
ligaments;  of  these  there  are  two  kinds,  true  and  false. 

The  ^rwe  ligaments  consist  of  the  pelvic  fascia:  they  are  attached  to 


84  ILLUSTRATIONS   OF   DISSECTIONS. 

the  neck  and  the  lower  part  of  the  bladder,  and  are  noticed  with  the  pre- 
ceding Plate  (p.  79). 

The  false  ligaments  are  formed  by  the  peritoneum,  and  are  five  in 
number,  viz.,  two  posterior,  two  lateral,  and  one  superior.  They  consti- 
tute a  wide  joiece  of  peritoneum,  reaching  from  the  side  of  the  bladder  to 
the  abdominal  wall,  which  is  subdivided  arbitrarily  into  the  parts  above 
said. 

The  upper,  which  is  single,  is  directed  from  the  apex  along  the  oblit- 
erated hypogastric  artery. 

The  lateral,  one  on  each  side,  is  attached  to  the  viscus  behind  the 
obliterated  hypogast]-ic. 

The  posterior,  also  one  on  each  side,  is  produced  by  the  hypogastric 
vessel  behind  the  back  of  the  bladder.  It  consists  of  a  doubling  of  the 
serous  membrane,  and  contains  the  remains  of  the  obliterated  vessel,  the 
ureter,  and  some  vesical  arteries.  Between  the  ligaments  of  opposite 
sides  tlie  serous  membrane  extends  downwards  as  the  recto-vesical  pouch. 

The  recto-vesical 2)oiLcU,  F,  is  the  piece  of  the  peritoneum  which  sinks 
between  the  bladder  and  the  rectum;  it  receives  its  name  from  its  position. 
Behind,  it  is  as  wide  as  the  interval  between  the  posterior  ligaments  of 
the  bladder,  but  in  front  of  it  tapers  to  a  point,  and  projects  slightly 
between  the  vesiculse  seminales.  Its  fore  part  is  distant  about  four 
inches  from  the  anus.  In  puncturing  the  bladder  through  the  rectum, 
the  surgeon  should  be  careful  not  to  carry  his  instrument  so  far  back  as  to 
injure  the  pouch,  because  in  that  case  the  urine  might  find  its  way  into 
the  cavity  of  the  abdomen,  and  would  give  rise  to  j)eritonitis.  But  the 
distention  of  the  bladder  affords  some  security  against  this  accident; 
since  the  viscus  enlarging  carries  upwards  the  peritoneum,  and  removes 
the  pouch  farther  from  the  anus. 

Generative  apparatus.  In  the  pelvis  are  contained  the  following 
accessory  generative  parts,  viz.,  the  vesicula  seminalis  and  vas  deferens, 
together  with  the  prostate. 

The  vas  deferens,  Gr,  is  the  excretory  duct  of  the  testicle,  and  conveys 
the  semen  to  the  urethra.  Separating  from  the  vessels  of  the  spermatic 
cord  at  the  internal  abdominal  ring,  it  crosses  the  obliterated  hypogastric 
artery,  and  then  descends  along  the  side,  to  the  under  part  of  the  blad- 
der, where  it  joins  with  the  vesicula  seminalis  to  form  the  common  ejac- 
ulatory  duct:  finally  it  ends  in  the  prostatic  part  of  the  urethra.     At  the 


CON'NECTIONS    OF    THE   PROSTATE.  85 

under  surface  of  the  bladder  it  is  placed  internal  to  the  vesicula  semi- 
nalis  of  the  same  side,  and  is  enlarged  and  slightly  sacculated. 

The  vesicula  seminalis,  B,  one  on  each  side,  is  a  small  sacculated 
reservoir  below  the  bladder,  wliicli  is  connected  with  the  vas  deferens, 
like  the  gall  bladder  with  the  biliary  duct.  Eather  larger  behind  than 
in  front  it  is  covered  by  a  layer  of  the  recto-vesical  fascia,  and  by  a  stra- 
tum of  involuntary  muscular  fibres;  and  it  forms  Avith  the  vas  deferens 
the  lateral  boundary  of  the  triangular  space  at  the  fundus  of  the  urinary 
bladder.  It  is  filled  with  the  fluid  secreted  by  itself,  and  contains  some 
spermatozoids  brought  by  the  vas  deferens. 

It  is  constructed  of  a  tube  bent  into  a  zigzag  form;  and  on  removing 
the  surrounding  fibrous  tissue  the  bends  disappear,  and  the  tube  measures 
from  four  to  six  inches.  In  front  it  becomes  narrowed,  and  joins  the 
vas  deferens  at  the  back  of  the  prostate  to  give  rise  to  the  common  ejacu- 
latory  duct. 

The  prostate  gland,  L,  surrounds  the  neck  of  the  bladder,  and  the 
beginning  of  the  urethra,  and  is  a  firm  muscular  and  glandular  body. 

Shaped  like  a  chestnut  with  the  larger  end  backwards,  it  measures 
one  inch  and  a  quarter  from  before  back,  one  inch  and  a  half  across  at 
the  base,  and  about  three  quarters  of  an  inch  in  depth.  Its  upper  surface 
is  convex,  and  the  under  is  flattened;  and  it  is  described  as  consisting  of 
a  median  and  two  lateral  lobes. 

Situate  between  the  triangular  ligament  of  the  urethra  and  the  blad- 
der it  is  placed  about  an  inch  below  the  pubes,  and  is  incased  in  a  sheath, 
as  before  said.  Its  upper  surface  is  connected  to  the  pubes  by  the  recto- 
vesical fascia  forming  the  anterior  true  ligament  of  the  bladder;  and  the 
under  surface  touches  the  rectum.  The  apex  is  in  contact  with  the  tri- 
angular ligament  of  the  urethra,  and  the  base  surrounds  the  neck  of  the 
bladder.  Through  this  body  the  urethra  is  directed  forwards  from  the 
bladder,  rather  above  the  centre;  and  the  two  common  ejaculatory  ducts 
are  inclined  obliquely  upwards  in  it  to  open  into  the  urethra. 

A  line  through  the  centre  of  the  prostate  has  a  different  direction  in 
the  standing  and  recumbent  postures.  In  the  erect  position  of  the  body 
it  curves  upwards  and  backwards  from  the  triangular  ligament;  but  when 
the  body  is  recumbent,  as  in  the  operation  for  stone,  the  axis  is  inclined 
downwards  and  backwards  from  that  membrane  towards  the  end  of  the 
sacrum.  This  change  in  the  axis  is  to  be  kept  in  mind  in  lithotomy, 
because  the  knife  is  to  be  directed  in  that  line  into  the  bladder. 


86  ILLUSTRATIONS    OF   DISSECTIONS. 

The  prostate  is  made  up  of  involuntary  musculary  fibres  wliich  are 
chiefly  circular.  Surrounding  the  fibres  externally  is  a  thin  membrane 
or  rind,  which  is  quite  distinct  from  the  sheath  derived  from  the  recto- 
vesical fascia  (p.  78). 

Some  glands  are  placed  below  the  urethral  tube,  projecting  amongst 
the  muscular  fibres:  they  open  into  the  floor  of  the  urethra  by  twelve  to 
twenty  ducts.  The  secretion  of  these  glands  is  poured  into  the  urethra, 
and  is  added  to  the  seminal  fluid  obtained  from  the  testicle  and  the  vesi- 
cula  seminalis. 

Curve  of  tlie  urethra.  The  bend  in  the  hinder  part  of  the  tube  of  the 
urethra  below  the  symphysis  pubis  constitutes  the  permanent  curve.  It 
reaches  from  the  bladder  to  about  an  inch  and  a  half  in  front  of  the  tri- 
angular ligament.  Its  convexity  is  turned  towards  the  perinseum  and 
the  rectum,  and  is  greatest  at  the  front  of  the  triangular  ligament  in  the 
erect  position  of  the  body.  From  this  point  it  is  inclined  upwards  and 
forwards  to  the  penis,  and  upwards  and  backwards  to  the  bladder. 

The  urethral  tube  is  kept  in  place  by  its  union  with  the  penis,  by  its 
passage  through  the  triangular  ligament,  and  by  the  recto-vesical  fascia 
around  the  prostate.  It  is  surrounded  completely  by  muscular  fibre,  in 
part  voluntary,  and  in  part  involuntary: — Thus  in  front  of  the  triangular 
ligament  it  is  incased  by  the  ejaculator  urinse — a  voluntary  muscle; 
between  the  layers  of  that  structure  the  voluntary  constrictor  urethras, 
with  a  thin  involuntary  stratum,  surrounds  the  tube;  and  behind  that 
ligament  the  urethra  is  included  in  the  thick  involuntary  mass  of  the 
prostate. 

In  the  passage  of  a  catheter  or  sound  along  the  urethra  the  greatest 
hindrance  is  met  with  in  the  urethral  curve,  and  especially  where  this 
passes  through  the  anterior  layer  of  the  triangular  ligament;  for  imme- 
diately before  that  membrane  the  urinary  passage  is  dilated  in  the  sinus 
of  the  bulb,  and  will  permit  the  point  of  the  instrument  to  deviate  from 
the  straight  line,  even  when  this  is  of  the  proper  size.  Beyond  the  liga- 
ment, obstruction  to  the  progress  of  the  instrument  can  scarcely  exist  in 
consequence  of  the  large  capacity  of  the  urethra. 

The  third  stage  of  the  lateral  operation  for  lithotomy  consists  in  divid- 
ing the  part  of  the  urethral  curve  behind  the  triangular  ligament.  The 
knife  having  opened  the  urethra  between  the  layers  of  the  triangular  liga- 
ment (p.  26)  is  carried  into  the  bladder  through  the  prostate.  To  give 
the  necessary  direction  to  the  incision  (p.  85)  the  handle  of  the  knife  is 


FIXED    CURVE    OF    THE    URETHBA.  87 

to  be  raised  above  the  level  of  the  blade,  and  the  edge  is  to  be  turned 
down  and  out.  The  lateral  part  of  the  prostate  is  to  be  incised,  so  as  to 
obtain  the  greatest  opening  in  that  body;  and  more  or  less  of  the  neck  of 
the  bladder  is  to  be  cut  through  according  to  the  size  of  the  calculus.  In 
the  division  of  those  parts  the  heel  of  the  scalpel  is  to  be  kept  near  the 
staff,  whilst  the  fore  part  of  the  blade  is  used  with  a  sawing  motion.  If 
the  stone  is  larger  than  can  be  removed  by  the  incision  on  one  side,  a 
similar  cut  is  to  be  jjractised  in  the  opposite  half  of  the  prostate. 

In  executing  the  third  stage  of  the  operation,  the  surgeon  endeavors 
to  cut  as  little  as  possible  of  the  loose  sheath  of  fascia  enveloping  the  base 
of  the  prostate  and  the  neck  of  the  bladder,  in  order  that  the  piece  of  the 
recto-vesical  fascia  separating  the  pelvic  cavity  from  the  j^erinseum  may 
remain  intact.  This  object  will  be  attained  most  certainly  by  keeping 
the  heel  of  the  knife  near  the  staff  as  above  directed;  for  if  the  hinder 
part  of  the  blade  is  too  far  removed  from  that  instrument  the  aperture 
into  the  bladder  will  be  necessarily  larger,  and  the  prostate  and  its  sheath 
may  be  totally  divided.-  It  is  just  possible  also,  if  the  prostate  is  slit  too 
largely,  that  the  "accessory  pudic"  artery  (Quain),  which  lies  occasion- 
ally on  the  side  of  the  jorostate,  may  be  wounded  with  fatal  result. 

Where  it  is  necessary  to  augment  still  more  the  opening  for  the  ex- 
traction of  a  large  calculus,  or  one  of  moderate  size  in  a  child,  the 
bladder  may  be  cut  in  the  same  line  as  the  prostate,  viz.,  as  nearly  as 
possible  along  the  upper  edge  of  the  vesicula  seminalis,  and  below  the 
attachment  of  the  lateral  ligament  of  the  recto-vesical  fascia.  To  me 
it  appears  safer  to  cut  that  viscus  in  a  direction  the  most  desirable,  than 
to  leave  it  to  tear  in  a  less  favorable  direction  under  the  influence  of  the 
force  used,  as  it  is  said,  for  the  dilatation  of  the  prostate. 

Stricture  of  the  urethra  is  most  common  at  the  fore  j)art  of  the  curve 
where  the  tube  is  covered  by  the  ejaculator  urinse  muscle;  it  has  its  seat 
but  seldom  m  the  membranous  part,  and  is  rare  in  the  prostatic  part  of 
the  canal. 

In  rupture  of  any  part  of  the  urethral  curve  the  urine  will  find  its  way 
to  the  scrotum  and  penis.  If  the  accident  is  situated  at  the  fore  part,  in 
front  of  the  triangular  ligament,  the  fluid  will  be  confined  and  directed 
forwards  by  the  superficial  fascia  (p.  17).  If  the  urine  escapes  between 
the  layers  of  the  ligament,  it  will  move  forwards  in  consequence  of  the 
anterior  layer  of  that  structure  being  less  resisting  than  the  posterior. 
And  even  Avhen  the  prostatic  part  is  broken  through,  the  urine  will  be 


88 


ILLUSTRATIONS    OF    DISSECTIONS. 


directed  forwards  to  the  triangular  ligament  as  long  as  the  sheath  of  fascia 
around  the  prostate  is  entire,  and  then  onwards  along  the  membranous 
part  of  the  tube. 


VISCERAL  ARTERIES  OF  THE  PELVIS. 

The  yisceral  arteries  are  furnished  from  different  sources: — Those  for 
the  bladder^,  and  the  generative  organs  beneath  it  are  derived  from  the 
internal  iliac  artery;  and  those  for  the  rectum  come  mainly  from  the  in- 
ferior mesenteric  artery — a  branch  of  the  aorta. 


a.  Common  iliac  artery. 
&.  Commoti  iliac  vein. 

c.  Obliterated  hypogastric. 

d.  Inferior  vesical  artery. 

e.  Branch  to  vesicula  and  prostate. 
/.  Branch  to  the  bladder. 

g.  Middle  vesical  artery. 
h.  Upper  vesical  artery. 


i.   Upper  hsemorrhoidal  artery. 

J- 
k. 

I     J 

m.  Gluteal  artery,  cut. 

20.  Sciatic  artery,  cut. 

r.  Branch  to  levator  ani,  cut, 


Branches  of  upper  hgemor- 
rhoidal  arteiy. 


The  vesical  arteries  are  two  or  three  in  number:  when  there  are  three, 
as  in  the  Plate,  they  have  the  undermentioned  distribution. 

The  upper  vesical,  h,  is  the  smallest,  and  accompanies  the  obliterated 
hypogastric,  of  Avhich  it  appears  to  be  a  pervious  part,  as  far  as  the  top 
of  the  bladder:  its  offsets  are  few,  and  inconsiderable  in  size. 

The  middle  vesical,  g,  supplies  the  body  of  the  bladder,  and  communi- 
cates with  the  other  arteries  of  that  viscus. 

The  inferior  vesical,  d,  ramifies  in  the  fundus  of  the  bladder,  and 
gives  branches  to  the  vesicula  seminalis,  B,  and  the  prostate,  L.  Usually 
it  furnishes  an  offset  to  the  rectum  (middle  haemorrhoidal),  but  in  this 
body  the  gut  was  not  supplied  by  it.  On  the  prostate  the  branches  be- 
come tortuous. 

HcemorrJioidal  arteries.  The  rectum  is  provided  with  vessels  from 
three  sources: — upper  haemorrhoidal,  i;  middle  hgemorrhoidal  from  the 
internal  iliac  (Plate  XLi.  g);  and  inferior  hsemorrhoidal  from  the  pudic 
artery  (Plate  xxix.  h). 

The  upper  licemorrlioidal,  i,  is  the  termination  of  the  inferior  mesen- 
teric trunk.  Placed  at  first  at  the  back  of  the  rectum,  it  divides  into 
six  or  seven  branches  about  the  middle  of  the  gut:  these  descend  around 


NEKVES    OF    THE    PELVIS. 


89 


the  intestine,  three  being  marked,  j,  k,  I,  and  pierce  the  muscular  coat 
about  three  inches  from  the  anus.  Inside  that  coat  the  branches  are  con- 
tinued nearly  to  the  anus,  where  they  communicate  together  in  a  series  of 
loops  beneath  the  mucous  membrane. 

The  vein  accompanying  the  artery  has  a  similar  looped  arrangement 
of  its  branches  within  the  anus;  and  these  loops  projected  through  the 
anus,  but  altered  in  their  structure  and  use,  form  hsemorrhoids  (p.  10). 


NERVES  OF  THE  PELVIS. 
Both  spinal  and  sympathetic  nerves  are  distributed  in  the  pelvis. 


1.  Vesical  nerves. 

2.  Nerve  to  levator  ani. 

3.  Nerve  to  coccygeus. 

4.  Sacral  plexus,  cut. 

5    Left  part  of  hypogastric  plexus. 


6.  Part  of  the  pelvic  plexus. 

7.  Offsets  of  the  knotted  cord  of  the 

sympathetic  to  hypogastric  plex- 
us. 


Spinal  nerves: — These  are  supplied  to  some  muscles,  and  to  the  viscera 
in  part. 

Only  two  of  the  mtiscular  branches  are  shown :  they  are  furnished  by  the 
fourth  sacral  nerve.  The  nerve  marked,  2,  belongs  to  the  levator  ani  of 
the  left  side,  and  enters  the  inner  surface;  another  nerve  to  the  coccygeus, 
3,  penetrates  into  the  fibres  on  the  pelvic  aspect  of  its  muscle;  and  the 
third  descends  to  the  perinaBum  to  supply  the  external  sphincter  (Plate 
XXIX.  5). 

Nerves  to  the  viscera,  1,  are  derived  from  the  fourth  or  the  third  sa- 
cral nerve,  and  occasionally  from  both  those  nerves;  they  supply  chiefly  the 
lower  part  of  the  bladder,  and  before  they  reach  that  viscus  they  commu- 
nicate freely  with  the  pelvic  plexus  of  the  sympathetic. 

Sympathetic  nerve.  One  part  of  the  sympathetic  is  distributed  al- 
together to  the  viscera,  and  the  other  is  a  knotted  cord  in  front  of  the 
sacrum:  a  similar  arrangement  exists  on  each  side  of  the  pelvic  cavity. 
Only  an  outline  of  the  visceral  part  is  here  sketched. 

Hyjmgastric  jylextcs.  In  front  of  the  sacrum  is  a  plexus  of  the  sym- 
pathetic with  this  name;  and  on  each  side  proceeds  an  offset,  5,  in  the 
form  of  a  flattened  band  Avithout  ganglia.     This  prolongation  communi- 


90 


ILLUSTRATIONS    OF    DISSECTIONS. 


cates  with  the  knotted  cord  lying  on  the  sacral  vertebrae  by  means  of  the 
small  nerves,  7,  7;  and,  below,  it  ends  in  the  pelvic  plexus. 

Pelvic  2}Iezus.  This  is  a  large  network  on  the  side  of  the  bladder  and 
rectum,  of  which  only  a  fragment  is  indicated  by  the  figures,  6,  6.  It 
receives,  above,  the  part,  5,  of  the  hypogastric  plexus,  and  is  joined  be- 
hind by  large  branches  from  the  spinal  sacral  nerves  in  the  pelvis.  Off- 
sets are  furnished  by  it  to  the  bladder  and  the  rectum,  and  to  the  vesicula 
seminalis,  penis,  and  urethra:  of  these  the  nerves  of  the  bladder  are  larger 
and  whiter  than  the  rest,  and  receive  more  spinal  nerve-fibres. 

A  view  of  this  plexus  has  been  omitted  from  the  Plate  because  its  dis- 
section is  in  general  too  difficult  for  the  student  to  execute,  and  because 
the  insertion  of  so  large  a  mass  of  nerves  would  interfere  with  the  sight  of 
the  pelvic  viscera. 


DESCRIPTION  OF  PLATE  XLI. 


A  SIDE  view  of  the  viscera  of  the  female  j)elvis  is  portrayed  in  this 
Figure. 

The  right  limb  was  detached  from  the  trunk  as  the  first  step  in 
the  dissection;  and  the  levator  ani  having  been  thrown  down,  the  fat 
and  fascia  were  removed  from  the  vessels  and  the  viscera.  The  perito- 
neum was  taken  away,  in  part,  to  demonstrate  the  extent  of  the  pouches 
of  that  membrane  before  and  behind  the  womb.  For  the  purpose  of  sup- 
porting the  hollow  viscera,  so  as  to  render  the  cleaning  of  them  more 
easy,  some  tow  was  introduced  into  the  rectum  and  vagina,  and  air  into 
the  bladder. 

CONNECTIONS  OF  THE  PELVIC  VISCERA. 

In  the  female  pelvis  are  contained  the  bladder  and  the  rectum  as  in 
the  male;  and  between  them  the  uterus  and  the  vagina  are  interposed. 


A.  Body  of  the  uterus. 

B.  Vagina. 

C.  Lower  part  ) 

}■  of  the  rectum. 

D.  Upper  part  J 


E.  Round  ligament  of  the  uterus. 

F.  Ovary. 

G.  Fallopian  tube. 
H.  Urinary  bladder. 


PLATE  XL 


CONNECTIONS    OF    THE    PELVIC    VISCERA.  91 


I.  Urethral  tube.  I       O.  Vesico-uterine  poiuli. 


J.  Ureter. 

K.  Triangular  ligament. 
L.  Constrictor  vaginae. 
M.  Psoas  niagnus,  cut. 
N.  Recto-uterine  pouch. 


P.  Levator  ani,  cut. 

Q.  Ligament  of  the  ovary, 

R.  Coccygeus  muscle. 

S.  Pyriformis,  cut. 

T.  Gluteus  niaximus,  cut. 


Rectum,  G,  D.  This  part  of  tli«  large  intestine  lias  the  same  extent 
and  curve  in  the  two  sexes;  but  iu  this  body  there  was  a  deeper  indenta- 
tion than  usual  near  the  lower  end  of  the  sacrum. 

Behind  it  are  the  sacrum  and  coccyx;  and  in  front  it  touches  the 
uterus  and  vagina,  which  separate  it  from  the  bladder  and  urethra.  It 
pierces  the  recto-vesical  fascia,  like  the  gut  in  the  male,  and  is  uncovered 
by  peritoneum  for  about  three  inches  below.  Its  vessels  and  nerves  are 
similar  to  those  in  the  male. 

Bladder,  H.  Like  the  corresponding  organ  in  the  other  sex,  it  is  the 
most  anterior  and  superficial  of  the  pelvic  viscera,  but  it  does  not  descend 
so  low  in  the  cavity  of  the  pelvis  as  in  man. 

Its  form  differs  somewhat  from  that  of  the  male  bladder:  thus  it  is 
less  deep,  and  is  wider  below  from  side  to  side  than  from  before  back; 
the  under  part  or  base  is  flatter,  and  does  not  project  so  much  below  the 
urethra. 

The  connections  of  the  body  of  the  viscus  with  parts  around  are  simi- 
lar to  those  of  the  male  at  each  side,  and  in  front;  but  they  differ 
below  and  behind.  Posteriorly  the  bladder  touches  the  uterus;  and  infe- 
riorly  it  rests  upon  the  vagina. 

The  urethra,  I,  is  a  short  narrow  passage  which  reaches  from  the  blad- 
der to  the  vulva.  It  measures  about  one  inch  and  a  half  in  length,  and 
is  therefore  much  shorter  than  the  urine-tube  in  the  male. 

Its  position  is  above  the  vagina,  and  in  its  course  to  the  exterior  of 
the  body  it  has  the  following  connections.  At  first  it  is  surrounded  by 
the  vascular  structure  of  the  vagina,  so  as  to  seem  to  form  one  mass  with 
that  tube  before  a  separation  has  been  made  by  dissection;  then  it  pierces 
the  triangular  ligament  of  the  urethra,  and  is  surrounded  by  the  fibres  of 
the  constrictor  urethrae  muscle  between  the  layers  of  that  structure;  and 
lastly  it  ends  in  the  bottom  of  the  vulva,  about  a  quarter  of  an  inch  above 
the  opening  of  the  vagina. 

This  short  canal  of  the  female  answers  to  the  prostatic  and  membran- 
ous parts  of  the  male  urethra  (Plate  xl.). 


92  ILLUSTRATIONS    OF    DISSECTIONS. 

The  ureter,  J,  differs  from  the  corresponding  tube  of  the  other  sex  in 
having  a  longer  course  in  the  pelvis,  and  in  crossing  the  side  of  the 
uterus  before  it  reaches  the  bladder. 

The  uterus,  or  womb,  A,  is  a  thick  muscular  viscus  with  a  small 
central  cavity  for  the  reception  of  the  ovum.  Somewhat  pyramidal  in 
form,  with  the  larger  end  upwards,  and  flattened  from  before  back,  it 
measures  about  three  inches  in  length,  two  in  breadth,  and  one  in 
thickness. 

Its  upper  end,  large  and  rounded,  is  named  the  fundus.  About  two- 
thirds  down  it  decreases  much  in  size;  and  this  narrowed  part,  neck  or 
cervix,  is  received  into  the  vagina,  B.  The  intermediate  part  of  the  viscus 
is  the  body.  The  anterior  surface  is  flattened;  the  posterior  is  rounded; 
and  the  narrow  sides  slo|)e  gradually  towards  the  neck.     • 

The  cavity  in  the  interior  is  flat  andtriangular:  it  communicates  below 
with  the  vagina  by  an  oval  opening,  or  the  mouth  of  the  uterus,  os  tincce; 
and  on  each  side  above  is  a  small  round  aperture  into  the  Fallopian 
tube,  G. 

The  uterus  and  the  vagina  are  interposed  between  the  bladder  and 
the  rectum;  and  the  womb  is  supported  in  its  place  by  ligaments  connect- 
ing it  to  the  abdominal  wall.  In  the  unimpregnated  condition  the  uterus 
is  placed  below  the  brim  of  the  pelvis;  and  it  sinks  down  lower  in  the  dead 
body.  Its  upper  end  is  directed  forwards,  and  the  lower  backwards;  and^ 
a  line  through  the  centre  would  correspond  Avith  the  axis  of  the  inlet  of 
the  pelvis;  if  that  line  was  prolonged  upwards  it  would  touch  the  ab- 
dominal wall  a  little  above  the  pubes. 

The  anterior  flattened  surface  touches  the  back  of  the  bladder,  and  is 
covered  in  part  by  peritoneum:  commonly  the  serous  membrane  reaches 
only  half  or  two-thirds  down,  and  the  cervix  is  united  by  fibrous  tissue  to 
the  bladder;  but  in  the  body  from  which  the  Figure  was  taken  the  whole 
of  the  anterior  surface  was  clothed  by  that  membrane.  The  posterior 
surface,  rounded,  is  turned  to  the  rectum,  and  is  entirely  covered  by 
peritoneum. 

The  upper  end  is  in  contact  with  the  small  intestines,  which  descend 
into  the  pelvis  in  the  Avoman;  and  the  lower  end  is  received  into  the 
vagina  in  such  a  way  as  to  be  covered  higher  behind  than  in  front. 

On  each  side  the  uterus  gives  insertion  to  a  broad  fold  of  peritoneum 
which  is  attached  externally  to  the  wall  of  the  pelvis,  and  divides  the 
cavity  into  two — an  anterior,  containing    the  bladder,  and  a  posterior. 


'     PERITONEUM    IN    THE    PELVIS.  93 

the  rectum.  In  this  fold  are  included  the  three  uterine  appendages,  viz. . 
the  Fallopian  tube,  G;  the  round  ligament,  E,  and  the  ovary  and  its  liga- 
ment, P,  and  these  are  placed  from  above  down  in  the  order  in  which 
they  are  here  enumerated. 

The  vagina,  B,  is  a  tube  which  reaches  from  the  uterus  to  the  vulva 
on  the  exterior  of  the  body.  It  takes  a  curved  course  in  front  of  the 
rectum,  and  below  the  bladder  and  urethra.  The  fore  part  is  shorter  than 
the  hinder;  and  a  line  through  it  would  correspond  with  the  axes  of  the 
cavity  and  outlet  of  the  pelvis. 

When  distended  it  is  roundish  in  form,  but  in  the  natural  state  it  is 
flattened  from  before  back  except  at  the  ends.  It  measures  about  five 
inches  in  length. 

In  its  course  it  pierces  the  recto- vesical  fascia,  receiving  from  this  a 
sheath  on  the  lower  half;  and  it  is  transmitted  through  the  lower  part 
of  the  triangular  ligament  of  the  urethra.  The  upper  end  is  attached 
to  the  neck  of  the  uterus,  reaching  farther  on  the  posterior  than  the 
anterior  surface,  and  the  lower  end  is  surrounded  by  the  constrictor 
vaginae  muscle,  L.  At  the  outer  orifice  in  the  child,  and  in  the  virgin 
state,  there  is  an  incomplete  occluding  structure  called  the  hymen. 

The  constrictor  vagince,  L,  is  an  orbicular  muscle  around  the  end  of 
the  vagina.  It  is  attached  in  front  on  each  side  to  the  clitoris:  from  this 
spot  the  fibres  pass  back  on  the  sides  of  the  vaginal  aperture,  and  end  at 
central  point  of  the  perineum,  some  joining  the  external  sphincter  ani. 

The  muscle  constricts  the  vagina;  and  possesses  at  one  time  a  volun- 
tary, and  at  another  an  involuntary  action,  like  the  ejaculator  uringe  by 
which  it  is  represented  in  the  other  sex. 

Peritoneum  in  the  pelvis.  The  serous  membrane  is  reflected  over  the 
viscera  so  as  partly  to  cover  and  fix  them  to  the  wall  of  the  pelvis,  after 
a  similar  manner  in  both  sexes. 

Surrounding  the  upper  half  of  the  rectum  it  attaches  the  gut  to  the 
wall  behind  by  a  fold— the  meso-rectum.  In  front  of  the  intestine  it  is 
reflected  on  the  back  of  the  vagina  and  the  posterior  surface  of  the 
uterus,  and  forms  the 'recto-uterine  pouch  between  the  womb  and  the 
rectum.  On  each  side  of  the  uterus  it  is  extended  outwards  in  a  wide 
piece  to  the  side  of  the  pelvis,  giving  rise  to  the  broad  ligament,  which 
contains  and  supports  the  Fallopian  tube,  G,  the  round  ligament,  E,  and 
the  ovary  with  its  ligament,  F.  The  membrane  may  be  then  traced  over 
the  front  of  the  uterus  to  the  back  of  the  bladder,  and  forms  between 


94  ILLUSTRATIONS    OF    DISSECTIONS. 

those  viscera  the  vesico-uterine  pouch.  And  finally  it  coyers  all  the  poste- 
rior surface  of  the  bladder  included  between  the  two  obliterated  hypogas- 
tric arteries,  c. 

The  recto-uterine  pouch,  N,  of  the  peritoneum  resembles  the  recto- 
vesical in  the  male.  Below  it  reaches  beyond  the  uterus  and  touches  the 
back  of  the  vagina.  On  each  side,  as  in  the  male,  are  the  visceral  arte- 
ries and  the  ureter,  invested  by  the  serous  membrane. 

The  vesico-uterine  pouch,  0,  intervenes  between  the  bladder  and  the 
uterus,  and  extends  downwards  usually  only  two-thirds  of  the  anterior 
surface  of  the  womb,  but  in  the  body  from  which  the  Figure  was  taken 
it  was  prolonged  (as  behind)  as  far  as  the  tube  of  the  vagina,  with  which 
it  was  in  contact. 

Appendages  of  the  uterus.  These  are  inclosed  in  the  broad  ligament, 
and  are  three  in  number  on  each  side,  viz.  Fallopian  tube,  round  liga- 
ment, and  ovary  and  its  ligament. 

The  Fallopian  tube,  G,  lies  along  the  upper  free  edge  of  the  broad 
fold  of  the  peritoneum,  and  is  about  four  inches  in  length.  By  the  inner 
end  it  is  attached  to  the  body  of  the  uterus,  and  at  the  outer  it  termi- 
nates in  a  free  dilated  extremity — the  inf  undibulum  or  pavilion.  Between 
tlie  extremities  it  has  a  curved  condition  with  the  convexity  up;  and  it  is 
small  and  round  near  the  uterus,  but  gradually  enlarges  towards  the 
outer  or  trumpet-shaped  end.  It  is  a  hollow  tube;  internally  it  commu- 
nicates with  the  cavity  of  the  uterus,  and  externally  by  a  small  aperture 
with  the  sac  of  the  peritoneum. 

The  outer  end  is  provided  with  points  or  fringes  called  fimbrim,  and 
with  folds  of  the  mucous  membrane  within.  Some  of  these  are  larger 
than  the  others;  and  in  the  bottom  of  the  dilatation  is  the  aperture  of 
the  tube  surrounded  by  the  folds. 

Its  ofiice  is  to  convey  the  ovum  from  the  ovary  to  the  uterus;  and  a 
muscular  layer,  continuous  with  that  in  the  wall  of  the  uterus,  enters 
into  its  structure. 

The  round  or  suspensory  ligament  of  the  uterus,  E,  is  contained  in 
the  fore  part  of  the  broad  ligament,  near  the  top,  and  is  inserted  into  the 
uterus  close  below  and  before  the  Fallopian  tube.  About  five  inches  in 
leogth,  it  is  directed  outwards  from  the  cavity  of  the  belly  through  the 
internal  abdominal  ring  and  the  inguinal  canal  to  the  groin,  where  it 
blends  with  the  subdermic  areolar  tissue.  In  the  abdominal  cavity  it  is 
invested  by  the  peritoneum;  and  in  the  inguinal  canal  it  is  accompanied 


VISCERAL    ARTERIES    OF    THE    PELVIS. 


95 


for  a  sliort  distance  by  a  process  of  that  membrane,  which  is  sometimes 
pervious  to  a  small  extent. 

This  band  consists  of  fibrous  tissue,  and  of  muscular  fibres  contin- 
uous with  those  of  the  uterus;  and  its  office  is  to  assist  in  supporting 
the  womb. 

The  ovary,  F,  is  an  ovalish  body,  something  like  the  testicle  in  form, 
which  is  situate  at  the  back  of  the  broad  uterine  fold  of  the  peritoneum, 
and  below  the  other  two  appendages. 

It  it  whitish  in  color,  with  more  or  less  of  an  irregular  surface;  and 
it  measures  about  an  inch  and  a  half  in  length  in  the  child-bearing  period 
of  life.  Its  position  is  horizontal,  with  the  ends  directed  inwards  and 
outwards:  it  is  attached  to  the  uterus  internally  by  a  special  fibrous 
band — ligament  of  the  ovary,  Q;  and  externally  it  is  connected  by  one  of 
the  fimbrise  to  the  trumpet-shaped  mouth  of  the  Fallopian  tube. 

This  body  contains  a  spongy  substance  surrounded  by  a  dense  fibrous 
coat;  and  the  whole  is  invested  by  the  serous  membrane.  There  is  not 
any  excretory  canal  attached  to  it,  for  the  Fallopian  tube  discharges  the 
office  of  conveyer  of  its  generative  products. 

In  the  ovary  the  ova  arc  produced;  and  when  these  small  bodies  are 
matured  they  burst  through  the  external  coats,  and  are  received  into  the 
pavilion  of  the  Fallopian  tube,  which  grasps  the  ovary  at  the  time  of  their 
escape. 

The  Ligament  of  the  ovary,  Q,  is  a  narrow  fibrous  band  uniting  the 
inner  end  of  the  ovary  with  the  body  of  the  uterus:  it  lies  below  the 
Fallopian  tube  in  the  broad  ligament. 


VISCERAL  ARTERIES  OF  THE  PELVIS. 

The  viscera  common  to  both  sexes  receive  similar  arteries,  and  those 
peculiar  to  each  sex  have  special  vessels. 


a.  External  iliac  artery,  cut. 
6.  Internal  iliac  artery. 

c.  Obliterated  hypogastric. 

d.  Upper  vesical  artery. 

e.  Lower  vesical  artery. 
/.  Uterine  arteiy. 

g.  Middle  hsemorrhoidal. 
/i.  Vaginal  artery. 


i.    Branches  to  rectum. 

j.   Ending  of  pudic  artery. 

fc.  Gluteal  artery,  cut. 

I.    Ovarian  artery. 

n.  Branch  of  ovarian  to  uterus. 


j  Branches  of  upper  haetnorrhoi- 


dai  artery. 


96  ILLUSTKATIONS    OF   DISSECTIONS. 

Internal  iliac  artery,  h.  This  large  trunk  furnishes  visceral  and  pa- 
rietal branches  in  the  pelvis,  as  before  said,  p.  67;  but  only  the  arteries 
to  the  viscera  are  delineated  in  this  Plate. 

Common  visceral  hranches.  The  arteries  which  have  the  same  name 
and  general  distribution  in  the  male  and  female  are  the  vesical  and 
hgemorrhoidal. 

The  vesical  arteries,  two  in  number,  upper,  d,  and  lower,  c,  are  dis- 
tributed to  the  regions  of  the  bladder  indicated  by  their  names. 

The  middle  hcemorrhoidal  artery,  g,  ramifies  in  the  Avail  of  the  rectum, 
below  the  recto-uterine  pouch  of  the  peritoneum:  part  of  it  has  been  cut 
off. 

The  iqoper  limmoy^rlioidal  is  derived  from  the  aorta  in  both  sexes,  and 
its  distribution  is  referred  to  in  page  88.  Three  of  its  branches,  o,  p,  q, 
are  shown  on  the  lower  part  of  the  rectum,  coursing  down  to  pierce  the 
muscular  coat,  and  end  in  loops  within  it. 

Special  visceral  hranches.  Three  arteries  are  furnished  to  the  gene- 
;rative  organs  of  the  female,  viz.,  the  uterine,  the  vaginal,  and  the  ovarian, 
but  only  the  two  first  are  branches  of  the  internal  iliac. 

The  uterine  artery,/,  is  the  largest  visceral  branch  of  the  iliac  trunk, 
•and  is  remarkable  in  being  very  tortuous  on  the  womb.  At  first  it  is  di- 
rected forwards  beneath  the  peritoneum  to  the  neck  of  the  uterus;  at  this 
spot  it  ascends  along  the  side  to  the  fundus  of  that  viscus,  where  it  ends. 
Many  large  serpentine  branches  are  distributed  from  it  to  the  uterus,  and 
it  communicates  above  with  the  ovarian  artery.  Near  the  cervix  uteri  it 
..gives  some  branches  to  the  upper  part  of  the  vagina. 

The  vaginal  artery,  h,  courses  forwards  between  the  vagina  and  the 
rectum  to  the  lower  end  of  the  vagina,  where  it  terminates  in  small 
branches:  it  furnishes  many  offsets  to  both  tubes. 

The  ovarian  artery,  I,  corresponds  with  the  spermatic  artery  of  the 
male,  and  is,  like  this,  a  branch  of  the  abdominal  aorta.  Arising  from 
the  great  systemic  vessel  near  the  renal  artery,  it  enters  the  pelvis  by  the 
side  of  the  internal  iliac,  and  is  then  continued  onwards  across  that  cavity 
to  the  ovary.     This  artery  is  flexuous,  like  the  uterine. 

At  the  ovary  it  divides  into  branches,  which  enter  that  body.  One 
offset,  n,  runs  in  the  broad  ligament  to  the  upper  part  of  the  uterus,  and 
communicates  with  the  uterine  artery;  and  other  branches  are  continued 
between  the  layers  of  the  broad  fold  of  peritoneum  to  the  Fallopian  tube 
and  the  round  ligament. 


PLATE  XLI 


nj;rves  of  the  pelvis. 


97 


Nerves  of  the  pelvis.  The  nerves  of  the  muscles  have  been  omitted 
in  this  view  of  the  female  pelvis;  and  the  visceral  nerves  of  the  sympa- 
thetic have  been  taken  away,  as  in  the  dissection  of  the  male  pelvis,  be- 
cause they  would  obscure  the  view  of  the  viscera. 


1.  Nerves  in  the  sacral  plexus,  cut. 

2.  Lateral  part  of  the  hypogastric 

plexus. 


3,  3.  Parts  of  the  pelvic  plexus,  cut 
through. 


The  jjelvic  plexus  of  the  symphatic  nerve  (p.  90)  of  which  parts 3,  3, 
remain,  resembles  in  its  composition  the  like  plexus  of  the  male,  and  sup- 
plies the  viscera.  It  is  situate  by  the  side  of  the  vagina,  bladder,  and 
rectum;  and  it  furnishes  common  branches  to  the  bladder  and  rectum, 
like  those  of  the  male;  and  special  branches  to  the  uterus,  Fallopian  tube, 
and  vagina. 

An  ovarian  ijlexus  of  nerves  accompanies  the  ovarian  artery,  and  sup- 
plies the  ovary  and  the  uterus:  this  was  taken  away  in  the  dissection. 


ILLUSTRATIONS  OF  THE  LOWER  LIMB. 


DESCRIPTION  OF  PLATE  XLII. 


This  Figure  shows  the  dissection  of  the  superficial  vessels,  nerves  and 
glands,  as  well  as  that  of  the  fascia  lata  near  Poupart's  ligament. 

The  limb  being  abducted  from  its  fellow,  rotated  out,  and  sujoported 
with  the  hip  and  knee  in  a  semiflexed  position,  the  skin  and  the  subcu- 
taneous fat  were  removed,  whilst  the  vessels,  nerves  and  glands  contained 
in  it  were  dissected  out.  The  opening  for  the  saphenous  vein  should 
then  be  carefully  defined. 


98 


ILLUSTKATIONS    OF    DISSECTIONS. 


SUPERFICIAL  VESSELS,   NERVES  AND  GLANDS. 

The  cutaneous  arteries  and  veins  ramifying  in  the  integuments  of  the 
top  of  the  thigh  are  branches  of  the  femoral  trunks. 


a.  Superficial  pudic  artery. 

b.  Superficial  epigastric  artery. 

c.  Superficial    circumflex    iliac    ar- 

tery. 

d.  Saphenous  vein. 

e.  Superficial  pudic  vein. 


/.  Cutaneous  arteries  of  the  thigh. 
g.  Cutaneous  vein  of  the  front  of  the 

thigh. 
h.  Superficial  epigastric  vein. 
I.    Superficial  circumflex  iliac  vein. 


Arteries: — The  cutaneous  arteries  in  the  groin,  like  the  tegamentary 
vessels  in  other  parts,  are  very  irregular  in  their  arrangement:  their 
names  are  taken  from  tlicir  distribution. 

The  superficial  pudis  artery,  a,  pierces  the  deep  fascia  of  the  limb 
about  the  mid-line;  or  it  may  come  through  the  saphenous  opening,  as  in 
the  Figure;  having  entered  the  fat,  it  courses  upwards  and  inwards  to 
end  in  the  integuments  of  the  pubes,  penis,  and  scrotum.  See  also  Plate 
xxxii. 

A  second  superficial  pudic  artery,  which  lies  at  first  beneath  the  fascia 
lata,  is  delineated  in  Plate  xlv.,  and  will  be  referred  to  with  the  anatomy 
of  the  femoral  artery. 

The  superficial  epigastric  artery,  h,  appears  through  the  fascia  near 
Poupart's  ligament,  being  sometimes  united  with  the  preceding  small 
artery,  and  ascends  in  the  fat  of  the  belly  towards  the  umbilicus. 

The  superficial  circumfiex  iliac  artery,  c,  runs  outwards  at  first  beneath 
the  fascia  lata,  and  pierces  that  membrane  towards  the  outer  border  of 
the  thigh,  to  end  in  the  integuments.  Two  or  three  offsets  enter  the  fat 
at  intervals;  and  some  accompany  the  genito-crural  and  external  cuta- 
neous nerves. 

Other  unnamed  small  arteries,  which  accompany  the  nerves,  4  and  5, 
and  are  marked  with,  /,  are  derived  from  the  femoral  trunk  lower  down 
in  the  thigh. 

Superficial  veins.  The  companion  veins  of  the  superficial  arteries 
above  described  end  for  the  most  part  in  the  saphenous  vein. 


FASCIA    LATA    AND    THE    SAPHENOUS    OPENING.  99 

Internal  saphenous  vei7i,  d.  This  large  cutaneous  vein  reaches  from 
the  dorsum  of  the  foot  to  the  groin,  but  only  the  upper  part  is  laid  bare 
in  the  dissection.  As  now  seen,  the  vein  ascends,  internal  to  the  mid- 
line of  the  thigh,  to  about  an  inch  and  a  half  from  Poupart's  ligament, 
where  it  sinks  througli  an  opening  in  the  fascia  lata  to  enter  the  femoral 
trunk.  Near  its  ending  it  receives  the  superficial  pudic,  e;  the  epigas- 
tric, h;  and  the  circumflex  iliac  vein,  I,  Somewhat  lower  down  in  the 
thigh  it  is  Joined  usually  by  two  larger  branches; — one,  g,  formed  by  the 
veins  from  the  outer  surface  and  front  of  the  thigh,  and  the  other  by 
veins  from  the  inner  and  hinder  parts  of  the  limb. 

Superficialinguinal  glands.  These  glands  in  the  thigh  are  placed  on 
the  sides  of  the  saphenous  vein,  and  are  superficial  to  the  fascia  lata. 
Of  a  flattened  form  and  reddish  color,  tliey  vary  much  in  size  and  num- 
ber: in  this  body  they  were  rather  large,  and  not  numerous.  They 
receive  the  afferent  superficial  lymphatics  from  the  inner  and  fore  parts 
of  the  limb;  and  transmit  efferent  vessels  through  the  deep  fascia  to  com- 
municate with  deeper  lymphatics.  Irritation  of  the  surface  of  the  foot, 
or  of  the  inner  part  of  the  leg  and  thigh,  along  the  course  of  the  saphen- 
ous vein,  may  give  rise  to  swelling  and  suppuration  in  this  set  of  glands. 

Another  group  of  superficial  inguinal  glands  lies  transversely  along 
the  line  of  Poupart's  ligament.     See  Plate  xxxii. 

Cutaneous  nerves.  The  nerves  now  laid  bare  are  derived  from  the 
lumbar  plexus  (p.  69);  and  they  will  be  followed  farther  in  the  subse- 
quent dissection  of  the  thigh,  with  the  exception  of  the  ilio-inguinal. 


1.  Ilio-inguinal. 

2.  Crural  branch  of  genito-crural. 


4.  Middle  cutaneous  of  the  thigh. 

5.  Branch  of  the  internal  cutaneous 


3.  External  cutaneous.  of  the  thigh. 

The  ilio-inguinal  nevYe,  1,  issues  through  the  external  abdominal  ring, 
and  terminates  in  offsets  to  the  scrotum,  and  to  the  integuments  of  the 
thigh  internal  to,  and  rather  below  the  saphenous  opening. 

FASCIA  LATA  AND  THE  SAPHENOUS  OPENING. 

The  special  fascia  of  the  thigh,  or  the  fascia  lata,  gives  a  sheath  to  the 
limb,  and  serves  for  the  attachment  of  muscular  fibres  at  certain  points: 
it  is  pierced  also  by  apertures  for  vessels  and  nerves. 


100 


ILLUSTRATIONS    OF    DISSECTIONS. 


A .  Poupart's  ligament. 

B.  Fascia  of  Scarpa,  cut. 

C.  D.  Fascia  lata. 

E.  Falciform  edge  of  the  saphe- 

nous opening. 

F.  Inner      part    of     the     crural 

sheath.   Qi/yJU-r^^  ^^ ' 


G.  Inner  sharp  edge  of  the  saphenous 

opening. 
H.  Saphenous  opening. 
I.    Opaque  line  of  the  bloodvessels 

under  the  fascia, 
ft  Superficial  inguinal  glands. 


The  fascia  lata,  C,  forms  a  contiuiious  tube  around  the  thigh,  and  sends 
inward  j^rocesses  to  form  sheaths  for  the  muscles.  White  lines  on  the 
surface  indicate  the  position  of  the  intermuscular  septa.  Along  the  front 
of  the  thigh  is  a  wider  yellowish  line,  I,  which  marks  the  situation  of  the 
subjacent  femoral  vessels. 

Only  a  small  j)art  of  the  fascia  is  now  laid  bare,  and  through  it  the 
saphenous  vein  passes.  Outside  the  opening  for  the  vein  the  fascia  is 
united  above  to  Poupart's  ligament:  here  it  is  thick  and  strong,  and 
serves  to  keep  the  ligament  tense  and  closely  applied  to  the  joarts  beneath, 
so  that  it  assists  materially  in  checking  the  descent  of  a  piece  of  intestine 
beneath  that  tendinous  band.  Inside  the  opening  the  fascia  is  much 
thinner,  and  is  inserted,  into  the  pubes. 

Most  of  the  apertures  in  the  fascia  for  the  passage  of  the  superficial 
vessels  and  nerves  are  small,  but  that  for  the  saphenous  vein  is  large,  and 
is  called  the  saphenous  opening. 

The  sajjhenous  opening,  H,  is  placed  inside  the  line,  I,  of  the  femoral 
vessels,  and  is  much  larger  than  is  needful  for  the  passage  of  the  vein  and 
some  other  small  vessels.  Its  form  is  semilunar,  with  the  extremities 
directed  up  and  down.  Its  measurements  arc,  one  inch  and  a  half  to  two 
inches  in  length,  and  about  half  an  inch  across  at  the  widest  part;  but 
the  greater  width  in  the  Figure  is  due  to  the  fascia  being  raised  by  the 
distending  with  injection  the  subjacent  vessels. 

The  extremities  of  the  aperture  are  named  cornua:  the  upper  cornu 
touches  Poupart's  ligament,  and  the  lowe^r  is  distant  about  one  inch  and  a 
half  from  that  structure. 

The  edges  have  different  characters: — The  outer  is  crescentic  in  form, 
and  blends  with  the  subjacent  crural  sheath  E:  above,  where  it  is  thicker 
and  firmer,  it  unites  with  Gimbernat's  ligament  (part  of  the  insertion 
of  Poupart).  To  this  border,  which  is  not  free,  though  it  has  a  semilunar 
appearance,  the  term  falciform  process  or  edge  has  been  given;  and  the 
upper  part,  between  E  and  Poupart's  ligament  A,  has  been  called  by  some 


THE    SAPHENOUS    OPENING.  101 

the  femoral  ligament.  At  the  inner  side  of  the  opening  the  fascia  lata  is 
flattened  half  the  way  down  over  tlie  subjacent  iiectineus  muscle;  but 
thence  to  the  lower  cornu  it  presents  a  sharp  edge,  G,  which  is  continued 
below  into  the  falciform  part  of  the  outer  boundary. 

In  the  area  of  the  opening  appears  the  loose  membraneous  crural 
sheath  F.  To  the  sides  of  the  aperture  the  deeper  stratum  of  the  sub- 
cutaneous or  superficial  fatty  layer  is  connected  by  bands  of  fibrous  tissue; 
and  as  that  part,  stretching  over  the  opening,  is  pierced  by  many  small 
apertures  for  lymphatics  and  vessels,  it  has  been  named  the  crihriforni 
fascia. 

Through  this  large  aperture  pass  the  saphenous  vein,  lymphatics,  and 
one  or  more  small  superficial  vessels:  the  vein  enters  nearer  the  lower 
than  the  upper  cornu,  but  the  others  have  not  a  fixed  position. 

By  means  of  this  aperture  a  femoral  hernia  comes  forwards,  and  forms 
a  swelling  in  the  thigh;  and  as  the  saphenous  opening  serves  as  the  aper- 
ture of  exit  of  the  hernia  from  beneath  the  fascia,  it  answers  to  the  ex- 
ternal abdominal  ring  of  the  inguinal  hernia.  The  intestnie  escapes 
through  the  upper  part  of  the  opening  above  the  situation  of  the  vein, 
and  pushes  before  it,  while  protruding,  the  crural  sheath  in  which  it  de- 
scends, and  the  thin  cribriform  fascia  placed  over  that  hole.  As  the  her- 
nial tumor  enlarges  it  is  directed  upwards  upon  the  firm  outer  margin 
of  the  opening — the  part  above  E;  and  since  the  gut  makes  a  sharp  curve 
round  the  fascia  it  may  be  constricted  at  that  spot  by  the  thickened  falci- 
form process. 

The  condition  of  the  margins  of  the  aperture  as  to  tightness  and  loose- 
ness depends  upon  the  position  of  the  limb,  and  on  the  tension  of  the  rest 
of  the  fascia  lata.  When  the  thigh  is  bent  and  rotated  in,  the  margins  of 
the  saphenous  opening  are  rendered  lax;  but  if  the  thigh  is  extended  and 
rotated  out,  the  aperture  is  made  tighter  and  smaller,  and  the  outer  edge 
takes  on  the  characters  of  a  firm  constricting  band.  In  an  attempt  there- 
fore to  force  backwards  a  piece  of  protruded  intestine  into  the  abdomen 
the  position  of  the  limb  should  be  specially  attended  to,  for  success  may 
depend  upon  the  greatest  possible  laxity  being  given  to  the  edges  of  the 
saphenous  opening. 


102 


ILLUSTRATION 8    OF    DISSECTIONS. 


DESCRIPTION  OF  PLATE  XLIII. 


In  this  Plate  the  anatomy  of  the  crural  sheath  and  the  course  of  a 
femoral  hernia  may  be  studied. 

To  display  the  crural  sheath  and  its  vessels,  throw  down  a  triangular 
flap  of  the  fascia  lata.  The  fat  coming  into  view  after  the  fascia  lata  is 
raised  should  be  removed  carefully:  and  the  crural  sheath  should  be  de- 
tached with  the  handle  of  the  scalpel  from  Poupart's  ligament  before,  and 
from  a  deep  piece  of  the  fascia  lata  beneath  it.  Cut  then  transversely 
through  the  front  of  the  crural  sheath  as  is  shown  in  the  Figure;  and  re- 
move a  piece  of  the  areolar  sheath  around  the  artery  and  the  vein,  so  as 
partly  to  denude  those  vessels. 


ANATOMY  OF  FEMORAL  HERNIA. 

As  the  femoral  hernia  descends  into  the  thigh  it  passes  beneath  Pou- 
part's ligament,  and  inside  the  loose  crural  sheath  to  the  saphenous  open- 
ing. The  anatomy  of  those  parts  in  the  thigh  will  be  described  shortly 
before  the  hernia  is  referred  to. 


A.  Oblique   part  of  Poupart's  liga- 

ment. 

B.  Horizontal  part  of  the  ligament. 

C.  Fascia  lata  of  the  thigh. 

D.  Reflected  part  of  the  fascia. 

E.  Pubic  part  of  the  fascia. 


F.  Crural  sheath. 

G.  Femoral  artery. 
H.  Femoral  vein. 

I.   Inguinal  gland  in  the  crural  ring. 
K.  Crural  canal. 


Poupart's  ligament  separates  the  regions  of  the  thigh  and  abdomen, 
and  has  been  described  in  page  30.  From  its  being  attached  to  bone 
only  at  the  extremities,  and  arching  over  the  part  issuing  from  the  abdo- 
men to  the  thigh,  it  has  received  also  the  name  crural  arch. 

Between  its  terminal  attachments  the  band  is  curved  downwards  to 
the  thigh,  being  oblique  in  direction  externally,  and  almost  horizontal 
internally.     To  the  lower  border  the  fascia  lata  is  attached;  and  as  long 


PLATE  XLII 


.^ 


/ 


/ 


ANATOMY  OF  FEMORAL  HERNIA.  103 

as  this  membrane  is  entire  the  band  is  kept  arched,  but  as  soon  as  the  fas- 
cia has  been  cut  through  tlie  ligament  becomes  lax,  and  rises  towards  the 
abdomen.  The  space  included  between  the  ligament  and  the  hip-bone  is 
closed  at  the  outer  end  by  the  large  flexor  muscles  of  the  hip  (psoas  and 
iliacus),  and  at  the  inner  by  the  femoral  vessels  and  the  crural  sheath; 
the  fascife  too  lining  the  cavity  of  the  belly  assist  in  closing  the  interval 
(Plate  xxxY. ).  Between  the  ligament  and  the  muscles  there  is  not  space 
for  the  escape  of  the  intestine  from  the  abdomen,  but  there  is  room  for 
its  passage  in  the  crural  sheath. 

Poupart's  ligament  is  rendered  more  or  less  resisting  by  the  position 
of  the  limb.  For  instance  if  the  limb  is  straight,  as  in  standing,  the  cru- 
ral arch  is  tense;  and  if  the  thigh  is  rotated  out  at  the  same  time,  that 
band  is  made  as  tight  as  it  can  be.  "When  the  thigh  is  bent  on  the  abdo- 
men the  tendinous  cord  is  relaxed;  and  it  attains  its  greatest  degree  of 
looseness  if  the  limb  is  rotated  in  at  the  same  time.  Of  necessity  this 
tendinous  arch  may  act  as  a  constricting  band  to  a  piece  of  intestine 
descending  beneath  it  in  femoral  hernia. 

Deep  crural  arch.  A  thin  fibrous  band  across  the  front  of  the  crural 
sheath  has  received  this  name.  It  begins  about  the  middle  of  the  super- 
ficial crural  arch,  and  widening  internally  is  attached  to  the  iDCctineal 
line  of  the  pubes;  it  consists  mostly  of  a  thickening  of  the  membrane 
forming  the  fore  part  of  the  sheath. 

The  crural  sheath,  F,  is  a  loose  membranous  tube  around  the  femoral 
vessels,  and  is  derived  from  the  fascios  lining  the  cavity  of  the  belly.  It 
lies  under  the  inner  or  horizontal  part  of  the  crural  arch,  filling  the  inter- 
val not  occupied  by  muscle;  and  it  extends  downwards  about  two  inches 
before  it  blends  with  the  areolar  sheath  around  the  bloodvessels.  Up- 
wards, or  towards  the  abdomen,  the  fore  part  of  the  tube  may  be  traced 
into  the  fasJa  transversalis;  and  the  hinder  part  is  described  as  being 
continuous     ith  the  fascia  iliaca  (Plate  xxxv.). 

Flattened  from  before  back,  it  is  triangular  in  form,  with  the  base 
towards  Poupart's  ligament  and  the  apex  around  the  femoral  vessels.  Its 
outer  edge  is  straighter  than  the  inner.  This  funnel-shaped  tube  lies  in 
an  interval  between  two  pieces  of  the  fascia  lata;  in  front  of  it  is  the  re- 
flected part,  D,  and  behind  it  is  a  deeper  piece  of  the  same  fascia,  from 
both  whicli  it  can  be  detached  with  the  handle  of  the  scalpel.  Perforat- 
ing it  are  superficial  vessels  for  the  top  of  the  thigh,  and  the  genito-cru- 
ral  nerve. 


104r  ILLDSTKATIONS    OF   DISSECTIONS. 

This  tube  serves  as  a  casing  to  the  bloodvessels  passing  from  the 
abdomen  to  the  thigh,  and  corresponds  with  a  similar  sheath  on  the 
vessels  of  the  upper  limb  entering  the  axilla. 

Interior  of  the  brural  sheath.  On  cutting  through  the  front  of  the 
crural  sheath,  as  in  the  Figure,  the  included  space  will  be  seen  to  be 
larger  than  is  needed  to  lodge  the  femoral  vessels;  and  to  be  largest  inter- 
nally where  the  tube  slants  most. 

In  the  tube  are  contained  the  femoral  vessels,  each  invested  with  ?. 
sheath  of  areolar  tissue,  together  with  an  inguinal  gland.  The  vessels 
lie  side  by  side,  the  artery  being  external  and  near  to  the  outer  border  of 
the  tube;  they  are  united  together  closely  by  their  areolar  investments. 
When  a  piece  has  been  cut  out  of  each  areolar  sheath,  as  in  the  Plate,  the 
cut  edges  on  the  sides  of  the  vessels  will  appear  like  partitions  pass- 
ing from  the  front  to  the  back,  and  dividing  into  parts  the  contained 
sjDace.  Commonly  three  such  spaces  or  compartments  are  described  as 
resulting  from  two  septa  in  the  interior  of  the  crural  sheath,  viz.  an  ex- 
ternal containing  the  femoral  artery;  a  middle  one,  the  femoral  vein; 
and  an  inner  space,  K,  which  is  partly  filled  by  an  inguinal  gland. 

Through  the  inner  space  of  the  crural  sheath  a  piece  of  intestine 
descends  in  femoral  hernia;  and  names  have  been  given  to  parts  of  the 
iDassage  through  which  it  glides,  which  resemble  the  terms  apjDlied  to  parts 
of  the  passage  for  the  inguinal  hernia.  Thus  the  opening  into  the  crural 
sheath  from  the  cavity  of  the  belly  is  the  crural  ring;  the  space  in  the 
interior  of  the  sheath,  inside  the  vein,  is  the  crural  canal;  and  the  saphe- 
nous opening  in  the  fascia  lata  represents  the  aperture  of  exit. 

The  crural  ring,  or  the  abdominal  aperture  into  the  space  in  the 
crural  sheath,  is  placed  on  the  inner  side  of  the  femoral  vessels,  and  is  on 
a  level  with  the  crural  arch.  It  is  about  as  large  as  the  tip  of  the  fore 
finger,  and  measures  most  from  within  out:  it  is  closed  by  the  inguinal 
gland,  I,  which  lies  in  it,  and  by  the  sub-peritoneal  fat  (septum  crurale) 
and  the  peritoneum  which  stretch  across  it  above  the  gland. 

Its  bounding  parts,  and  the  vessels  around,  are  described  at  page 
50.     (Plate  XXXV.) 

The  crural  canal,  K,  is  the  narrow  space  inside  the  crural  sheath, 
which  is  internal  to  the  femoral  vein.  It  extends  from  the  crural  ring 
to  the  upper  cornu  of  the  saphenous  opening,  and  measures  from  half  to 
three  quarters  of  an  inch  in  length.  It  gradually  tapers  from  abov^ 
down,  being  pyramidal  in  form  with  the  base  upwards. 


COURSE  OF  FEMORAL  HERNIA.  105 

Contained  in  the  crural  sheath,  it  will  be  bounded  externally  to  that 
tube,  both  in  front  and  behind  by  fascia  lata;  and  it  is  closed  below  by 
the  meeting  of  the  femoral  vein  with  the  inner  slanting  side  of  the  crural 
sheath. 

The  saplienous  opening  is  concealed  by  the  reflected  piece  of  the  fascia 
lata;  but  it  is  delineated  in  Figure  xlii.  Its  boundaries,  size,  and  con- 
ditions, have  been  described  in  page  100.  By  means  of  this  aperture  the 
gut  comes  forwards  to  the  surface  of  the  thigh;  and  this  aperture  of  exit 
has  been  called  the  lower  opening  of  the  crural  passage. 

Course  of  femoral  hernia.  The  piece  of  intestine  in  femoral  hernia 
passes  beneath  the  crural  arch  and  within  the  crural  sheath  as  before 
said,  but  it  changes  its  direction  as  it  proceeds  onwards.  Entering  the 
crural  canal  through  the  abdominal  aperture,  it  descends  vertically  as 
far  as  the  upper  cornu  of  the  saphenous  opening.  Next  it  advances 
through  that  opening  to  the  surface  of  the  thigh,  making  at  first  a  small 
round  tumor,  but  as  more  of  the  gut  is  protruded  it  extends  transversely 
below  Poupart's  ligament.  Finally,  as  the  hernia  enlarges  it  ascends 
over  the  crural  arch  on  to  the  abdomen,  because  there  is  less  resistance 
in  this  direction  than  towards  the  thigh.  In  consequence  of  the  winding 
course  of  the  intestine  the  last  or  ascending  part  comes  to  be  parallel  al- 
most to  the  first  or  descending  part  of  the  tumor;  and  the  two  are  united 
below  by  a  curve  around  the  sharp  margin  of  the  saphenous  opening. 
In  attempts  to  reduce  a  large  femoral  hernia  the  bend  in  the  course  is  to 
be  specially  remembered,  and  the  contents  of  the  constricted  gut  are  to 
be  directed  down  and  back  to  the  upper  part  of  the  saphenous  opening. 

Whilst  the  intestine  remains  in  the  crural  canal  the  hernia  is  said  to 
be  incomplete;  but  if  the  gut  has  escaped  from  the  canal,  and  forms  a 
tumor  on  the  surface,  the  hernia  is  called  complete. 

Coverings  of  the  Iternia.  The  investments  applied  to  the  intestine  as 
it  descends  are  derived  partly  from  strata  in  the  abdomen,  and  partly 
from  structures  in  the  thigh.  In  the  first  place  the  gut  receives  a  sheath 
from  the  peritoneum,  which  forms  the  sac  of  the  hernia.  In  the  next 
place  it  pushes  onwards  and  elongates  the  layer  of  subperitoneal  fat 
(septum  crurale)  as  it  enters  the  crural  ring;  and  it  causes  the  inguinal 
gland  to  be  pushed  aside  or  absorbed.  With  those  two  strata  derived 
from  the  abdomen  it  traverses  the  crural  canal  as  far  as  the  saphenous 
opening;  and  at  that  point  it  will  obtain  the  next  two  coverings,  viz. 


106  ILLUSTRATIONS    OF    DISSECTIONS. 

those  of  the  crural  sheath  and  the  cribriform  fascia,  though  it  may  burst 
through  one  or  both  of  these.  And  lastly  it  stretches  and  forms  coverings 
for  itself  of  the  subcutaneous  fatty  layer  and  the  skin. 

Six  layers  are  thus  enumerated  as  the  coverings  of  a  complete  femoral 
hernia.  In  a  recent  tumor  the  several  strata  may  be  separated  from  each 
other;  but  in  an  older  large  hernia  the  coverings  derived  from  the  septum 
crurale  and  the  crural  sheath  are  conjoined,  and  form  the  fascia  propria 
of  Cooper.  During  an  operation  tbe  surgeon  may  be  able  to  recognize 
only  four,  viz.  the  skin  and  the  subcutaneous  fatty  layer,  the  fatty 
subperitoneal  covering,  and  the  peritoneal  sac. 

Diagnosis.  The  tumor  of  a  complete  femoral  is  generally  smaller 
than  that  of  an  inguinal  hernia;  and  its  deeper  part  or  neck  can  be  traced 
down  to  the  hollow  at  the  upper  and  inner  part  of  the  thigh,  that  is,  to 
the  upper  cornu  of  the  saphenous  opening.  Should  it  be  larger  in  size, 
it  extends  transversely  along  the  line  of  Poupart's  ligament,  instead  of 
descending  towards  the  scrotum  as  in  the  inguinal  hernia.  It  can  be  dis- 
tinguished with  certainty  from  the  inguinal  liernia  by  the  position  of  its 
neck  beneath  the  crural  arch;  and  if  the  finger  can  detect  the  cord  of 
Poupart's  ligament  passing  over  the  neck  of  the  tumor  there  cannot  be 
any  doubt  of  the  hernia  being  femoral. 

Taxis  and  truss.  Before  attempts  are  made  to  replace  the  intestine 
■in  the  cavity  of  the  abdomen,  the  limb  is  to  be  raised  and  rotated  in,  and 
the  shoulders  are  to  be  elevated  at  the  same  time,  with  the  view  of  relax- 
ing to  the  utmost  the  rigidity  of  the  fibrous  structures  amongst  which  the 
intestine  passes.  Then  pressure  is  to  be  made  with  one  hand  to  the  fun- 
dus of  the  tumor,  whilst  the  first  two  fingers  of  the  other  are  to  be 
applied  to  the  neck  of  the  hernia  to  direct  the  contents  of  the  intestine 
round  the  falciform  edge  of  the  saphenous  opening,  and  upwards  along 
the  crural  canal  to  the  cavity  of  the  abdomen.  Whilst  practising  the 
manipulation  the  force  employed  is  to  be  moderate  but  sustained.  If 
the  tumor  has  extended  upwards  on  the  abdomen  it  should  be  brought 
downwards  towards  the  saphenous  opening,  in  order  that  the  bend  around 
the  falciform  process  of  the  fascia  lata  may  be  lessened. 

After  the  hernia  has  been  reduced  its  re-descent  is  to  be  stopped  by 
a  truss;  but  as  the  pad  of  this  instrument  cannot  compress  the  internal 
crural  ring,  through  which  the  intestine  begins  to  descend,  it  is  to  be 
placed  below  Poupart's  ligament,  over  the  upper  and  inner  part  of  the 
saphenous  opening.  —   -    - 


STRICTURE    OF    FEMORAL    HERNIA.  107 

External  stricture.  The  strangulation  of  the  intestine  will  be  pro- 
duced generally  by  a  constricting  fibrous  band  across  and  outside  the 
neck  of  the  sac  of  the  hernia.  The  seat  of  the  constriction  may  be  at 
the  level  of  Poupart's  ligament  or  of  the  saphenous  opening,  but  both  are 
near  together,  the  spots  being  only  about  half  an  inch  apart.  In  the 
former  situation  it  is  occasioned  by  the  firm  edge  of  tlie  band  formed  by 
Gimbernat's  ligament  and  the  crural  arch:  and  in  the  latter,  by  the 
sliarp  margin  of  the  falciform  part  of  the  fascia  lata. 

This  stricture  may  be  relieved,  without  opening  the  sac  of  the  hernia, 
by  cutting  down  to  the  upper  and  inner  part  of  the  neck  of  the  tumor, 
just  below  Poupart's  ligament,  and  by  incising  all  constricting  bands 
external  to  the  sac,  whether  at  the  saphenous  opening  or  at  Gimbernat's 
ligament.  After  the  division  of  the  external  stricture,  a  slight  degree  of 
force  will  suffice  to  replace  the  intestine  in  the  cavity  of  the  abdomen. 

Internal  stricture.  Stricture  exists  sometimes  inside  the  sac  of  the 
hernia.  In  this  case  the  constriction  is  produced,  as  in  inguinal  hernia 
(p.  41),  by  a  thickening  of  the  peritoneum  of  the  neck  of  the  sac,  so  as 
to  form  a  band  which  diminishes  the  space  in  the  interior,  and  impedes 
the  passage  both  of  the  intestinal  contents,  and  of  the  blood  in  the  wall 
of  the  intestine.  Its  position  is  opposite  the  line  of  Gimbernat's  liga- 
ment and  the  crural  arch. 

As  the  kind  of  strangulation  cannot  be  determined  beforehand,  the 
coverings  of  the  hernia  are  to  be  divided  at  the  neck  of  the  tumor,  as 
in  the  case  of  the  external  stricture;  and  if  the  sac  cannot  be  emptied  of 
its  contents  after  cutting  through  all  constricting  parts  external  to  it, 
the  intestine  is  to  be  relieved  from  internal  stricture  by  opening  the  peri- 
toneal sac,  and,  the  knife  being  introduced  on  a  director  beneath  the 
thickened  band,  by  cutting  horizontally  inwards  towards  Gimbernat's 
ligament.  In  executing  this  last  part  of  the  operation  the  surgeon  does 
not  see  what  the  knife  cuts,  and  therefore  he  uses  it  sparingly,  for  as 
soon  as  the  string-like  band  is  divided  the  intestine  becomes  free  to  be 
passed  into  the  abdomen. 

In  Plate  xxxv.  an  inner  view  is  given  of  the  crural  ring  with  the  vessels 
around  which  may  be  endangered  in  an  operation;  and  in  page  52  are 
detailed  the  precautions  to  be  taken  in  setting  free  the  gut  from  internal 
stricture. 


108  ILLUSTRATIONS    OF    DISSECTIONS. 


SUPERFICIAL  VESSELS  AND   NERVES. 

The  cutaneous  vessels  and  nerves  which  are  figured  in  this  Plate  have 
been  described  in  page  98;  and  they  are  marked  for  the  most  part  with 
the  same  letters  and  figures  of  reference  as  in  the  preceding  Plate. 
Consequently  only  their  names  will  be  given  in  the  subjoined  tables. 


Vessels. 


a.  Superficial  pudic  artery. 
h.  Superficial  circumflex  iliac  artery. 
c.  Cutaneous  arteries  of  the  front  of 
the  thigh. 


Nerves. 


1.  Ilio-inguinal  nerve. 

2.  Crural  branch  of  genito-crural. 


d.  Internal  saphenous  vein. 

e.  Superficial  pudic  vein. 


3.  External  cutaneous  of  the  thigh. 

4.  Middle  cutaneous  of  the  thigh. 


DESCRIPTION  OF  PLATE  XLIV. 


A  SUEFACE  view  of  the  muscles  of  the  fore  and  inner  parts  of  the 
thigh,  with  the  cutaneous  nerves  placed  in  position  after  being  dissected. 

The  common  mode  of  proceeding  Avith  the  dissection  of  the  thigh  has 
been  here  departed  from,  with  the  view  of  keeping  within  bounds  the 
number  of  the  Plates.  Usually  the  subcutaneous  nerves  and  vessels  con- 
tained in  the  fat  are  first  traced  out.  Scarpa's  space  at  the  top  of  the  thigh 
is  next  laid  bare,  and  the  fascia  lata  is  then  removed  to  bring  into  view  the 
muscles.  If  it  is  wished  to  study  Scarpa's  space  separately  from  the  rest, 
let  the  lower  two-thirds  of  the  Plate  be  covered  with  a  piece  of  paper. 


SUPERFICIAL  NERVES  AND  VESSELS. 

The  cutaneous  nerves  of  the  front  of  the  thigh  are  either  direct  offsets 
of  the  lumbar  plexus,  or  are  derived  from  branches  of  that  plexus. 


PLATE  XLIV 


^    /  ^/ 


/    // 


i  0 


I      / 


^: 


H.Uoiickc,  l.lil,   f;  >. 


SUPERFICIAL    NERVES. 


109 


1.  Ilio-inguinal  nerve. 

2.  Crural  branch  of  geuito-crural. 

3.  External  cutaneous. 

4.  Anterior  crural  trunk. 

5.  Internal  cutaneous  of  the  thigh. 

6.  Anterior  branch  of  internal  cuta- 

neous. 

7.  Inner    branch    of  internal  cuta- 

neous. 


ft  Offsets  of  internal  cutaneous. 

8.  Middle  cutaneous  of  the  thigh. 

9.  Offset  of  internal  cutaneous  to 

the  patellar  branch  of  the  saphe- 
nous. 

10.  Patellar  branch  of  the  saphenous. 

11.  Internal  saphenous  nerve. 

12.  Offset  of  saphenous  to  the  leg. 

13.  Superficial  part  of  the  obturator. 


Ilio-ingtiinal  nerve,  1.  This  small  branch  of  the  lumbar  j)lexus  has 
been  noticed  in  page  70;  and  it  has  been  delineated  in  the  preceding 
Plates. 

Genito-crural  nerve.  The  crural  part,  2,  of  this  nerve  issues  beneath 
Poupart's  ligament  at  the  spot  here  indicated,  when  it  is  larger  than  usual; 
but  commonly  it  lies  nearer  to  the  femoral  vessels,  as  shown  in  Plate 
XLiii.,  where  it  is  seen  to  perforate  the  crural  sheath.  It  comes  through 
the  fascia  lata  near  Poupart's  ligament,  and  ramifies  in  the  fat  about  half 
way  down  the  thigh.  Before  or  after  it  pierces  the  fascia  it  joins  the 
middle  cutaneous  nerve,  8;  and  in  the  body  used  for  the  dissection,  a 
junction  took  place  under  the  fascia  lata  with  the  external  cutaneous 
nerve,  3. 

The  external  cutaneous  nerve,  3,  leaves  the  abdomen  beneath  the  outer 
end  of  Poupart's  ligament,  and  becomes  subcutaneous  about  four  inches 
from  that  band.  It  extends  in  the  fat  as  low  as  the  knee,  and  supplies 
branches  to  the  outer  and  hinder  parts  of  the  thigh,  behind  a  line  drawn 
from  the  front  of  the  iliac  crest  to  the  outer  edge  of  the  patella.  One  or 
two  small  branches  pierce  the  fascia  lata  at  a  point  higher  than  the  trunk 
of  the  nerve. 

Anterior  crural  nerve,  4.  This  large  trunk  of  the  lumbar  plexus  (p. 
70)  passes  from  the  abdomen  below  Poupart's  ligament;  and,  lying  out- 
side the  crural  sheath,  divides  into  cutaneous  and  muscular  branches. 
The  superficial  branches  are  the  three  following,  viz.  the  internal  and 
middle  cutaneous,  and  the  internal  saphenous.  The  muscular  branches 
are  shown  in  Plate  xlvi. 

The  middle  cutaneous  of  the  tliigli,  8,  enters  the  fat  about  three  inches 
from  Poupart's  ligament:  it  extends  to  the  knee  along  the  centre  of  the 
thigh,  distributing  offsets  laterally,  and  ends  in  the  integuments  over  the 


110  ILLU8TBATION8    OF    DISSECTIONS. 

patella.  Most  commonly  the  nerve  is  subdivided  into  two;  or  there  may 
be  two  distinct  nerves. 

Internal  cutaneoics  of  the  thigh,  5.  Springing  from  the  anterior  crural 
with  the  preceding,  it  descends  beneath  the  fascia  lata  and  along  the  edge 
of  the  sartorius,  or  under  the  muscle,  as  far  as  the  junction  of  the  upper 
and  middle  thirds  of  the  thigh,  where  it  divides  into  two  parts,  which 
are  distributed  as  below: — 

The  anterior  branch,  6,  winds  forward  over  the  sartorius,  A,  and 
piercing  the  fascia  lata  in  the  lower  third  of  the  thigh,  supplies  the  in- 
teguments as  low  as  the  inner  side  of  the  knee:  it  joins  the  patellar  branch 
of  the  great  saphenous  nerve  by  the  offset,  9. 

The  inner  branch,  7,  courses  under,  and  along  the  hinder  border  of 
the  sartorius  to  the  inner  side  of  the  knee,  where  it  is  transmitted  through 
the  fascia  lata;  when  cutaneous  it  is  continued  m  the  fat  along  the  inner 
part  of  the  calf  of  the  leg,  about  half-way  down.  Near  its  beginning  it  is 
joined  by  a  branch,  13,  of  the  obturator  nerve,  and  on  the  inner  part  of 
the  knee  there  is  a  uniting  branch,  9,  between  it  and  the  great  saphenous 

nerve. 

From  the  trunk  of  the  nerve  before  it  divides,  or  from  its  anterior 
branch,  offsets  marked  thus,  f,  are  furnished  to  the  integuments  of  the 
inner  part  of  the  thigh  in  the  upper  half. 

The  internal  saphenous  nerve,  11,  lying  at  first  beneath  the  sartorius, 
as  is  seen  in  Plate  xly.,  escapes  from  beneath  that  muscle  at  the  inner 
side  of  the  knee;  and  is  continued  with  the  vein  of  the  same  name  through 
the  leg  to  the  foot.  As  it  becomes  cutaneous  it  gives  forwards  one  offset 
to  the  integuments  of  the  front  of  the  leg,  and  another  backwards  to  join 
the  inner  branch,  7,  of  the  internal  cutaneous. 

Whilst  the  saphenous  neiwe  is  covered  by  the  sartorius  in  the  lower 
third  of  the  thigh  it  supplies  o,  patellar  branch,  10,  to  the  integuments  of 
the  inner  and  fore  parts  of  the  knee:  this  pierces  the  sartorius  and  the 
fascia,  and  being  joined  by  an  offset,  9,  of  the  internal  cutaneous, 
communicates  in  the  fat  with  the  middle  and  external  cutaneous  nerves, 
forming  a  plexus — the  patellar. 

Part  of  the  obturator  nerve.  The  superficial  part,  13,  of  the  obturator 
nerve  comes  forwards  beneath  the  abductor  longus  muscle,  H,  and  is  in- 
clined outwards  under  the  sartorius  muscle  and  the  fascia  lata  to  tlie 
femoral  artery  (Plate  xlv.).  It  communicates  with  the  internal  cuta- 
neous branch,  7,  beneath   the   fascia;   and  some    small  offsets  are  pro- 


■Scarpa's  triangular  space.  Ill 

longed  through  the  fascia  to  the  integuments  on  the  inner  side  of  the 
thigh. 

Siqierficial  vessels.  Small  arteries,  for  the  most  part  unnamed;  and 
the  internal  saphenous  vein  and  its  tributaries  ramify  in  the  fat  of  the 
thigh. 

•  Cutaneous  arteries.  All  the  cutaneous  nerves  are  accompanied  by 
superficial  arteries;  but  as  these  are  small,  and  not  so  easily  traced  as  the 
firmer  nerves,  they  were  not  dissected  farther  than  was  necessary  to  give 
an  idea  of  their  main  parts. 

Ramifying  with  the  ilio-inguinal  nerve,  1,  is  a  branch  from  the  cre- 
masteric artery;  with  the  genito-crural  nerve,  2,  and  external  cutaneous, 
3,  are  branches  from  the  superficial  circumflex  iliac;  with  the  middle 
cutaneous,  8,  and  internal  cutaneous,  5,  are  small  branches  of  the  femoral 
trunk;  with  the  saphenous  nerve,  11,  and  with  its  branches,  10,  and  22, 
are  offsets  of  the  anastomotic  artery;  and  with  the  obturator  nerve,  13, 
runs  a  small  branch  of  the  internal  circumflex  artery. 

Other  cutaneous  arteries  issue  beneath  the  edges  of  the  sartorius  mus- 
cle, being  furnished  from  the  femoral  trunk;  and  many  small  offsets, 
piercing  the  fleshy  fibres  of  the  vasti  and  rectus,  come  from  the  vessels  to 
those  muscles. 

The  internal  saphenous  vein,  p,  lies  in  the  fat  with  the  superficial 
nerves  along  the  inner  part  of  the  thigh.  Below,  it  passes  the  knee-joint 
on  the  inner  side,  behind  the  prominence  of  the  inner  condyle,  and  as- 
cends obliquely  to  the  level  of  the  hip-joint,  where  it  pierces  the  fascia 
lata  to  join  the  deep  vein.  See  Plate  xlii.  Large  unnamed  branches 
join  it  about  the  knee,  and  smaller  veins  enter  it  in  the  thigh;  and  it  re- 
ceives near  its  ending  the  named  veins  accompanying  the  small  superficial 
arteries  of  the  groin. 


SCARPA'S  TRIANGULAR  SPACE. 

The  triangular  interval  at  the  top  of  the  thigh  answers  to  the  axilla 
in  the  upper  limb.  It  is  a  rather  shallow,  intermuscular  s]3ace,  which  is 
situate  on  the  flexion-side  of  the  hip  joint,  and  contains  the  main  vessels 
of  the  limb,  with  the  nerve  of  the  front  of  the  thigh. 

Its  boundaries  are  the  following: — The  base,  directed  upwards  to  the 
abdomen,  is  limited  by  Poupart's  ligament:  in  the  dissected  limb  this 


112  ILLUSTRATIONS    OF    DISSECTIONS. 

band  forms  a  straight  line,  but  before  the  removal  of  tlie  fascia  it  arches 
down  below  the  level  of  the  arteries,  h,  and  c,  and  diminishes  the  length 
of  the  space.  The  apex  is  formed  by  the  meeting  of  the  sartorius.  A,  and 
abductor  longus,  H,  and  points  to  the  inner  side  of  the  mid-line  of  the 
thigh. 

Towards  the  surface  this  space  is  closed  by  the  strong  fascia  lata,  and  by 
the  teguments  and  the  inguinal  glands  :  this  covering  will  vary  in  thick- 
ness according  to  the  quantity  of  fat  in  the  body.  The  floor  or  the  deep 
boundary  is  limited  by  the  iliacus,  D,  and  psoas,  at  the  outer  part;  and 
at  the  inner  part,  by  the  pectineus,  G,  adductor  longus,  H,  and  still 
nearer  tlie  femoral  vessels  by  a  small  piece  of  the  adductor  brevis. 

The  hollow  is  deepest  near  the  middle,  where  the  bloodvessels  lie,  and 
gradually  becomes  shallower  from  that  point  towards  each  side.  It  con- 
tains the  femoral  artery  and  vein,  with  their  first  branches,  the  anterior 
crural  nerve,  and  lymphatics  and  fat. 

The  femoral  artery,  a,  lies  along  the  centre  or  deej)est  jiart  of  the  in- 
termuscular interval,  resting  above  on  the  psoas  muscle,  and  furnishing 
the  large  profunda  and  small  superficial  branches:  it  leaves  the  space  be- 
low by  sinking  under  the  sartorius,  about  an  inch  outside  the  apex. 

The  femoral  vein,  in,  lies  close  to,  and  on  the  inner  side  of  the  artery, 
gradually  winding  beneath  that  vessel  near  the  sartorius  muscle.  Like 
the  artery  it  is  most  superficial  at  Poupart's  ligament;  and  at  that  spot 
it  rests  on  the  pubes,  between  the  pectineus  and  psoas  muscles.  In  the 
space  it  is  joined  by  the  saphenous  or  superficial,  and  by  deep  veins. 

The  anterior  crural  nerve,  4,  enters  the  space  on  the  outer  side  of  the 
artery,  and  may  lie  close  to  that  vessel,  as  in  the  Plate,  or  at  a  short  dis- 
tance from  it  (quarter  to  half  an  inch).  Above  it  lies  deeply  between  the 
iliacus  and  psoas,  and  is  separated  from  the  artery  by  a  slip  of  muscular 
fibres.  About  two  inches  from  Poupart's  ligament  it  breaks  up  into 
superficial  and  muscular  branches;  but  before  this  final  division  it  sends 
one  or  two  small  branches  beneath  the  femoral  vessels  to  the  pectineus 
muscle. 

Deep  lymphatics  lie  around  the  femoral  vessels,  and  receive  superficial 
lymphatics  near  Poupart's  ligament;  upwards  they  are  continued  into  the 
abdomen. 


SURFACE  Muscles  of  the  front  of  xke  thigh. 


113 


SURFACE  MUSCLES  OF  THE  FRONT  OF  THE  THIGH. 

Only  one  muscle — the  sartorius,  A,  is  completely  laid  bare  in  the  sur- 
face view  of  the  fore  and  inner  parts  of  the  Miigh.  Inside  or  above  the 
sartorius  are  two  groups  of  muscles,  the  flexors  of  the  hip  and  adductors 
of  the  thigh;  and  outside  the  sartorius  lies  the  extensor  group  of  the 
knee.  Altogether  at  the  upper  and  outer  part  appears  a  small  muscle 
(tensor  vaginse  femoris).  which  belongs  to  the  abductor  or  gluteal  set  of 
muscles. 


A.  Sartorius  muscle. 

B.  Tendon  of  the  sartorius. 

C.  Tensor  vaginse  femoris. 

D.  niacus  muscle.     -4  (^s<;ti/J 

E.  Rectus  femoris. 

F.  Vastus  internus. 


G.  Pectineus  muscle.  ^ 
H.  Adductor  longus.  ? 

I.  Gracilis  muscle.   ^ 

J.  Tendon  of  adductor  magnus. 
X.  Spot  for  ligature  of  the  femoral 
artery. 


The  sartorius,  A,  is  the  longest  muscle  in  the  body.  It  crosses 
obliquely  the  thigh  from  the  hip-bone  on  the  outer  side  to  the  tibia  on 
the  inner,  and  lies  in  a  hollow  between  the  adductors  of  the  thigh  and 
extensors  of  the  knee. 

The  muscle  is  narrow  at  the  origin,  and  is  attached  to  the  upper  iliac 
spinous  process,  and  to  half  the  notch  between  the  two  spinous  processes. 
The  fibres  form  a  thm  widened  belly  on  the  thigh,  and  end  below  in  a 
short  flat  tendon,  B,  which  is  inserted  into  the  inner  surface  of  the  tibia 
near  the  tubercle:  from  the  upper  border  of  the  tendon  one  expansion  is 
continued  to  the  knee-joint  capsule,  and  from  the  lower  border  another 
is  prolonged  to  the  fascia  of  the  leg. 

The  sartorius  conceals  the  greater  part  of  the  femoral  vessels,  and  the 
branches  of  the  interior  crural  nerve.  It  rests  on  the  following  muscles : 
— along  the  inner  edge,  from  above  down,  come  the  iliacus,  D,  pectineus, 
G,  adductor  longus,  H,  gracilis,  I,  and  the  inner  hamstrings;  and  along 
the  outer  edge  are  the  tensor  vaginse  femoris,  C,  rectus,  E,  vastus  inter- 
nus, F,  and  tendon  of  the  adductor  magnus,  J.  Just  above  the  knee  it 
bounds  the  po|)liteal  space  with  the  inner  hamstrings;  and  this  part  is 
pierced  by  the  patellar  branch,  10,  of  the  saphenous  nerve. 


114  ILLUSTRATIONS    OF    DISSECTIONS. 

The  action  of  the  muscle  is  exemplified  in  the  posture  of  squatting. 
By  its  contraction  the  hip-bone  is  drawn  forwards,  the  tibia  backwards, 
and  the  fascia  lata  is  rendered  tense  at  the  same  time.  If  the  pelvic  end  is 
fixed  and  the  tibia  free,  the  knee-joint  will  be  bent;  and  if  the  tibial  extrem- 
ity becomes  the  fixed  point  the  pelvis  Avill  be  supported  and  drawn  for- 
wards. In  standing  on  one  leg,  say  the  right,  the  muscle  of  the  same  side 
will  assist  in  turning  inwards  the  pelvis  on  the  top  of  the  femur,  and  in 
rotating  the  trunk  to  the  left  side:  with  the  left  muscle  acting  in  the 
same  way  the  trunk  will  be  moved  in  the  opposite  direction. 

Flexor  muscles  of  the  hip-joiiit.  These  are  two  in  number,  viz.  the 
psoas  and  iliacus  (p.  58);  but  only  the  latter,  D,  is  now  visible,  as  the 
psoas  is  concealed  by  the  femoral  artery.  Both  arise  in  the  abdomen, 
and  issue  thence  beneath  Poupart's  ligament  to  be  inserted  into,  and  in 
front  of  and  below  the  small  trochanter  of  the  femur. 

The  adductor  muscles  of  the  thigh  form  the  large  fleshy  mass  at  the 
inner  side  of  the  femur;  they  are  five  in  number,  but  only  three,  viz. 
pectineus,  G,  adductor  longus,  H,  and  gracilis,  I,  are  in  contact  with 
the  fascia.  All  will  be  more  completely  laid  bare  in  subsequent  Plates; 
and  in  Figure  XLVii.  the  deeper  members  of  the  group  are  exhibited. 

The  extensors  of  the  knee-joint  are  three  large  muscles,  which  make 
the  bulge  on  the  fore  part  of  the  thigh:  they  consist  of  rectus  femoris, 
E,  vastus  internus,  F,  and  vastus  externus  (L,  Plate  xlvi.).  Above, 
they  are  concealed  for  a  short  distance  by  the  sartorius.  A,  and  tensor 
vaginae  femoris,  C;  and  below,  they  blend  in  a  common  tendon,  which  is 
continued  over  the  knee-joint  to  the  tibia.  Plate  xlvi.  is  specially 
devoted  to  the  anatomy  of  these  muscles,  and  of  the  vessels  and  nerves 
belonging  to  them. 


PLATE  XLV, 


I  /  '  ' 


/ 


/ 


/r 


A  ,      I     / 


i< 


2  ,  <r 


'  ¥  h  ^' 


\  v\.      'W- 


SURFACE    MUSCLES    OF    THE    FRONT    OF    THE    THIGH.  1.15 


DESCRIPTION  OF  PLATE  XLY. 


The  anatomy  of  the  femoral  vessels  and  anterior  crural  nerve  may  be 
acquired  from  this  Figure. 

After  the  completion  of  the  dissection  for  the  preceding  Plate  the 
chief  nerve  and  vessels  on  the  front  of  the  thigh  will  be  brought  into 
view  by  removing  the  cutaneous  nerves,  and  by  taking  away  the  greater 
part  of  the  sartorius  muscle.  On  the  removal  of  the  fat  and  an  aponeu- 
rosis beneath  the  sartorius  the  nerve  and  vessels  will  be  visible. 


SURFACE  MUSCLES  OF  THE  FRONT  OF  THE  THIGH. 

The  connections  of  the  several  superficial  muscles  can  be  perceived  in 
this  Figure;  but  the  description  of  each  will  be  given  subsequently  with 
the  group  of  muscles  to  which  it  belongs :  they  are  marked  by  the  same 
letters  of  reference  as  in  Plate  xliv. 


A.  Ends  of  the  sartorius. 

B.  Gluteus  maximus. 

C.  Tensor  vaginge  femoris. 

D.  Iliacus. 

E.  Rectus  femoris. 

F.  Vastus  internus. 


G.  Pectineus. 

H.  Adductor  longus. 

I.     Gracilis. 

J.    Adductor  magnus. 

K.  Semi-membranosus. 


FEMORAL  ARTERY  AND  VEIN. 


The  main  bloodvessels  of  the  lower  limb,  like  those  of  the  upper,  are 
large  single  trunks  as  far  as  one  bone  reaches  in  the  member,  and 
divide  into  branches  in  the  leg  where  two  bones  are  present. 


116 


ILLUSTRATIONS    OF    DISSECTIONS. 


a.  Femoral  artery. 

*    Spot  for  ligature. 

&.  Circumflex  iliac  branch. 

c.  Epigastric  branch. 

d.  Superficial  circumflex  iliac. 

e.  Superficial  pudic. 

/.  Deeper  superficial  pudic. 
g.  Profunda  artery. 
h.  Anastomotic  artery. 


i.    Superficial  branch  of  anastomotic. 

f    Cutaneous  arteries  of  the  femoral. 

j.    Ending  of  external  iliac  artery. 

Jc.  Femoral  vein. 

I.    Superficial  pudic  vein. 

n.  Deeper  superficial  pudic. 

o.  Profunda. 

p.  Saphenous  vein,  cut. 


The  femoral  artery,  a,  is  continuous  directly  with  the  external  iliac, 
and  reaches  beyond  the  knee,  like  the  brachial  beyond  the  elbow,  before 
it  breaks  up  into  secondary  trunks.  Its  extent  is  marked  in  one  direction 
by  the  lower  border  of  Poupart's  ligament,  and  in  the  other  by  the  open- 
ing in  the  adductor  magnus:  finally  it  turns  to  the  back  of  tlie  limb,  by 
this  aperture,  and  obtains  the  name  popliteal. 

Its  course  in  the  limb  is  oblique;  for  near  the  pelvis  the  vessel  lies 
over  the  hip-jomt,  whilst  it  is  placed  inside  the  femur  below.  And  its 
position  in  the  thigh  would  be  marked  by  a  line  on  the  surface  from  mid- 
way between  the  symphysis  pubis  and  iliac  crest  to  the  prominence  of  the 
inner  condyle  of  the  femur,  when  the  knee  is  half  bent,  and  the  thigh  bone 
rotated  out.  Pressure  applied  to  the  artery  in  the  middle  third  of  the 
thigh  should  therefore  be  directed  outwards  towards  the  femur;  and  when 
employed  above,  it  must  be  made  directly  backwards  against  the  hip-bone. 

At  the  top  of  the  thigh  the  vessel  is  near  the  surface  and  is  uncov- 
ered by  muscle,  but  in  the  rest  of  its  extent  it  is  concealed  by  the  sar- 
torius  (see  Plate  xliv.).  In  the  description  of  its  connections  the  ar- 
tery will  be  divided  into  a  superficial  and  a  deep  part. 

Tlie  siLjjerficial  pari  (Plate  xliv.)  is  contained  in  Scarpa's  triangul  r 
space,  and  measures  from  three  to  four  inches  in  length  according  to 
the  width  of  the  sartorius  muscle.  It  lies  nearly  in  the  centre  of  the 
space,  and  its  position  in  the  limb  may  be  ascertained  by  means  of  the 
upper  part  of  the  line  before  given  for  the  course  of  the  femoral  trunk. 

At  first  the  artery  is  incased  in  the  crural  sheath  with  the  femoral 
vein  (Plate  xliii.).  Between  it  and  the  surface  of  the  limb  lie  the  com- 
mon teguments  with  inguinal  glands,  and  the  fascia  lata.  The  vessel 
rests  at  first  on  the  psoas  muscle,  and  is  placed  lower  down  over  the  pec- 
tineus,  G,  but  at  some  distance  from  it,  the  profunda  and  circumflex 
vessels  with  fat  intervening. 


.FEMORAL    ARTERV    AND    VEIN.  117 

To  the  iinicr  side  iind  close  to  tlio  iirtcry  lies  the  femoral  vein,  wliich 
inclines  graduiiUy  behind  that  vessel  towards  the  apex  of  the  space. 

Outside  the  artery,  either  close  to,  or  at  a  little  distance  from  it,  is 
the  anterior  crural  nerve:  this  divides  into  many  branches  in  the  space 
of  Scarpa;  and  of  these,  the  internal  cutaneous,  5,  crosses  over  the  artery 
near  to  or  beneath  the  sartorius. 

The  deei)  jmrt  of  the  artery  (Plate  xlv.)  is  contained  in  an  inter- 
muscular interval  on  the  inner  side  of  the  femur,  which  has  been  called 
Hunter's  canal.  Superficial  to  the  vessel  in  this  hollow  is  the  sartorius, 
A;  with  an  aponeurotic  layer  beneath  that  muscle,  which  is  stretched 
between  the  vastus  internus,  F,  and  the  adductor  longus  and  magnus 
muscles,  H  and  J:  this  layer  does  not  appear  in  the  Figure,  as  it  was 
removed  in  the  dissection.  Beneath  the  vessel  lie  the  adductors,  viz, 
pectineus,  G-  (the  lower  end),  adductor  brevis  (a  small  piece),  adductor 
longus,  II,  and  adductor  magnus,  J.  On  the  outer  side  is  the  vastus 
internus,  which  separates  the  artery  from  the  femur.  Inferiorly  the  ar- 
tery issues  from  that  space  through  the  aperture  in  the  adductor  magnus 
muscle. 

The  femoral  vein  is  closely  applied  to  the  artery  throughout,  and 
winds  behind  it  from  the  inner  to  the  outer  side.  The  superficial  or 
internal  saphenous  vein  has  a  position  inside  the  bloodvessel,  but  often- 
times an  external  branch  of  that  vein  crosses  the  line  of  the  artery  (Plate 

XLII,   (j). 

The  internal  saphenous  nerve,  13,  runs  with  the  artery;  it  is  outside 
that  vessel  above,  but  inside  below,  and  crosses  beneatii  the  aponeurosis 
over  the  artery. 

Position  and  size  of  the'hranches.  Most  of  the  unnamed  branches  of 
the  femoral  artery  are  small  in  size  and  cutaneous,  and  arise  at  tolerably 
regular  intervals  along  the  trunk.  From  the  beginning  come  three  small 
named  branches  (Plate  xlii.),  viz.  superficial  epigastric,  h,  circumflex 
iliac,  c,  and  pudic,  a.  Two  inches  lower  down  arises  the  large  profunda 
trunk,  (J,  for  the  supply  of  the  thigh.  And  close  to  the  ending  springs 
the  small  anastomotic  artery,  h,  for  the  knee-joint. 

Of  these  branches  the  profunda  is  the  largest;  and  to  it  the  term  deep 
femoral  has  been  given.  It  arises  commonly  from  the  second  inch  of  the 
femoral  trunk,  varying  much  as  to  its  site  within  that  limit;  but  its 
origin  takes  often  a  much  wider  range  as  the  observations  of  Mr.  Quain 


118  ILLUSTRATIONS    OF   DISSECTIONS. 

have  demonstrated.*  Thus  it  may  be  attached  to  the  first  inch  of  the 
femoral,  or  even  higher,  so  as  to  come  from  the  end  of  the  external  iliac. 
Or  it  may  leave  the  parent  vessel  lower  in  the  thigh,  arising  as  far  as  four 
inches  from  Poupart's  ligament;  but  in  this  state  of  deviation  its  circum- 
flex branches  are  usually  attached  higher  up  and  separately  to  the  femoral 
trunk.  As  the  beginning  of  this  large  vessel  ranges  then  over  the  upper 
four  inches  of  the  femoral  artery  a  ligature  cannot  be  applied  to  that  part 
of  the  vessel  without  the  prospect  of  subsequent  hsemorrhage. 

Ligature  of  the  femoral.  As  this  vessel,  like  the  artery  of  the  upper 
limb,  is  conveniently  placed  for  the  employment  of  pressure  to  control 
the  circulation  of  the  blood,  the  operation  of  tying  it  with  a  thread  for 
the  treatment  of  aneurism  in  the  popliteal  space  will  be  resorted  to  but 
rarely;  but  should  such  a  proceeding  be  required  the  following  directions 
may  be  useful  in  its  execution. 

The  spot  chosen  for  ligature  is  determined  by  the  place  of  origin  of 
the  profunda,  as  the  surgeon  desires  to  jDlace  the  thread  on  the  femoral 
trunk  beyond  that  large  nutritive  and  anastomic  branch.  But  as  the 
origin  of  the  profunda  wanders  over  the  highest  four  inches  of  the  femo- 
ral artery,  a  spot  between  four  and  five  inches  from  Poupart's  ligament, 
which  is  marked  thus,  X,  in  the  figure,  is  to  be  selected  as  the  most  suit- 
able for  that  operation,  even  though  the  vessel  is  not  so  accessible  as  it 
would  be  in  Scarpa's  triangular  space. 

The  position  of  the  femoral  artery  in  the  limb  may  be  ascertained  by 
a  line  on  the  surface  from  the  mid  point  between  the  iliac  crest  and  the 
symphysis  pubis  to  the  inner  condyle  of  the  femur,  the  hip  and  knee-joints 
being  slightly  bent  at  the  time,  and  the  thigh  rotated  out.  This  line  is 
to  serve  both  as  the  superficial  and  the  deep  guide;  and  if  it  is  not  accu- 
rately taken  and  strictly  kept  some  difiiculty  may  be  experienced  in  find- 
ing the  artery,  as  there  is  not  any  deep  part  to  direct  the  operator  to  the 
position  of  the  bloodvessel. 

In  executing  the  steps  of  the  operation  the  fore  finger  of  the  left  hand 
is  placed  opposite  the  part  of  the  vessel  to  be  tied,  and  the  knife  incises 
the  integuments  for  three  inches,  the  centre  of  the  cut  being  marked  by 
the  finger;  and  as  there  may  be  a  large  branch  of  the  saphenous  vein  cross- 
ing the  artery  the  knife  should  be  used  cautiously  at  this  stage.  The 
fascia  lata  should  next  be  cut  for  the  same  extent  as  the  skin  and  fat. 

*ln  the  work  before  referred  to  on  the  Surgical  Anatomy  of  the  Arteries. 


BRANCHES    OF    THE    FEMORAL    ARTERY.  119 

Then  the  fibres  of  the  sartorius,  which  are  inclined  downwards  and  in- 
wards, Avill  appear  in  the  bottom  of  the  wound.  This  muscle  is  next  to 
be  reflected  with  care  from  the  artery,  and  to  be  drawn  to  the  outer  side 
of  the  wound;  and  underneath  the  spot  occupied  by  the  sartorius  the 
femoral  artery  may  be  recognized  during  life  by  its  pulsation,  and  in  the 
dead  body  by  its  color. 

The  next  stej?  is  to  detach  the  artery  from  the  surrounding  parts. 
For  this  purj)ose  seize  the  areolar  sheath  with  a  forceps,  and  open  it  with 
a  part  of  the  scalpel  at  some  little  distance  from  the  point,  avoiding  if 
possible  the  internal  cutaneous  nerve.  The  sheath  being  still  held  in  the 
forceps,  separate  the  artery  from  this  and  the  companion  vein  by  a  blunt 
instrument,  such  as  a  director,  introduced  through  the  opening  in  the 
areolar  investment. 

Eaising  the  sheath  with  the  forceps  the  operator  introduces  the  aneu- 
rism needle  between  the  artery  and  vein;  and  then  elevating  the  opposite 
side  of-  the  sheath,  he  passes  the  instrument  gently  round  the  artery. 
Finally  setting  free  the  thread  from  the  needle  in  the  usual  way,  the  sur- 
geon ligatures  the  femoral  trunk;  but  in  the  living  body  he  ascertains 
beforehand  that  the  vessel  pulsates  on  compression  with  the  finger.  Gen- 
tleness and  tact  are  required  in  passing  the  needle,  lest  the  instrument 
should  pierce  either  of  the  large  bloodvessels;  but  if  the  aneurism  needle 
is  carried  from  right  to  left,  puncture  of  either  is  less  likely  to  happen 
than  if  it  is  moved  in  the  opposite  direction. 

Should  the  artery  be  deprived  of  its  sheath  to  a  greater  extent  than  is 
needed  for  the  passage  of  the  aneurism  needle,  it  should  be  secured  by 
two  ligatures — one  at  each  end  of  the  denuded  part. 

On  reaching  the  artery  the  operator  may  find  the  origin  of  the  pro- 
funda at  that  point,  or  possibly,  though  but  rarely,  the  femoral  trunk 
split  into  two: — In  each  case  he  would  include  both  vessels  in  ligatures. 

Usually  the  femoral  vein  is  not  seen  in  the  operation  specified;  but  if 
it  is  split,  or  if  one  of  its  pieces  crosses  over  the  artery,  it  may  be  in  the 
way  of  the  knife  in  opening  the  sheath. 

Branches  of  the  femoral  artery.  The  first  three  branches  are  small 
and  cutaneous,  and  are  named  superficial  pudic,  epigasti'ic,  and  circum- 
flex iliac:  these  have  been  noticed  with  Plate  xlii.  Another  superficial 
pudic  branch  is  the  following. 

The  inferior  or  deeper  superficial  pudic  arises  from  the  femoral  trunk 
rather  lower;  it  runs  beneath  the  fascia  lata  and  the  gracilis  muscle  to  the 


120  ILLUSTRATIONS    OF   DISSECTIONS. 

inner  side  of  the  thigh,  where  it  ends  in  the  teguments  of  the  limb  and 
scrotum,  and  in  the  labium  pudendi  of  the  female.  Small  collateral  off- 
sets are  furnished  to  the  muscles  with  which  it  is  in  contact. 

The  profunda  artery,  g,  arises  about  an  inch  and  a  half  below  Pou- 
part's  ligament,  and  descends  in  the  thigh  beneath  the  femoral  artery,  as 
IS  shown  in  Plate  xlvii.  It  supplies  large  nutrient  and  anastomotic 
branches  to  the  thigh. 

Cutaneous  and  muscular  branches.  The  small  arteries  to  the  integu- 
ments which  are  marked  thus,  f,  have  been  described  in  page  111.  The 
muscular  branches  from  the  femoral  trunk  are  but  few:  they  enter  the 
vastus  internus,  sartorius,  and  adductor  longus. 

The  anastomotic  artery,  li,  springs  from  the  end  of  the  femoral,  and 
IS  continued  between  the  vastus  internus  and  the  tendon  of  the  adductor 
magnus  to  the  inner  side  of  the  knee:  here  it  ramifies  under  the  apo- 
neurotic investment  of  the  joint,  and  anastomoses  with  the  other  articular 
arteries.  Offsets  are  given  by  it  to  the  vastus  internus,  one  crossing  the 
lower  end  of  the  femur  above  the  joint. 

A  superficial  branch  of  the  anastomotic,  i,  accompanies  the  trunk  of 
the  saphenous  nerve  beneath  the  sartorius,  and  ends  in  the  integuments 
with  that  nerve. 

The  femoral  vein,  Jc,  is  a  companion  to  the  artery,  and  has  the  same 
extent.  Closely  united  throughout  to  the  artery  it  changes  its  position 
to  that  vessel  about  the  middle  of  the  thigh,  for  it  is  on  the  inner  side 
above,  but  on  the  outer  side  below.  Near  Poupart's  ligament  it  is  placed 
over  the  interval  between  the  psoas  and  pectineus,  but  farther  in  the 
thigh  it  has  connections  with  parts  around  like  those  of  the  artery. 

Its  branches  are  similar  for  the  most  part  to  those  of  the  artery,  but 
they  have  been  taken  away  in  the  progress  of  the  dissection.  Near  the 
top  of  the  thigh  it  receives  in  addition  the  superficial  or  saphenous  vein; 
and  at  the  same  place  it  is  joined  by  the  small  vein,  w, -accompanying  the 
deeper  of  the  two  superficial  pudic  arteries. 


ANTERIOR  CRURAL  NERVE. 

This  large  nerve  of  the  lumbar  plexus  (p.  70)  divides  in  Scarpa's  tri- 
angular space  into  a  superficial  and  a  deep  set  of  branches. 

The   superficial  set  consists  of  internal  cutaneous,  middle  cutaneous, 


ANTERIOR  CRURAL  NERNE,  121 

and  internal  saphenous;  but  as  the  middle  cutaneous  has  been  noticed 
sufficiently  with  Plate  xliv.  it  will  not  be  referred  to  again. 

The  internal  cutaneous  nerve,  5,  inclines  beneath  the  sartorius  to  the 
inner  side  of  the  thigh,  and  divides  into  two  parts,  anterior  and  inner. 

The  anterior  part,  6,  is  delineated  in  Figure  xliv.,  and  its  description 
is  given  in  page  110. 

The  inner  part,  7,  descends  along  the  inner  border  of  the  sartorius 
nearly  to  the  knee,  where  it  becomes  a  cutaneous  nerve  of  the  leg  (Plate 
XLIV.).  Near  its  beginning  it  is  joined  by  an  offset  from  the  obturator, 
15;  and  lower  down  (occasionally)  by  a  branch,  8,  from  the  internal  saphe- 
nous.    See  also  p.  110. 

The  internal  saiJhenous  nerve,  13,  courses  beneath  the  sartorius,  and 
at  the  insertion  of  that  muscle  becomes  cutaneous  below  the  knee:  it  is 
then  continued  through  the  leg  to  the  foot.  For  two-thirds  of  its  extent 
in  the  thigh  it  accompanies  the  femoral  vessels,  crossing  over  them  from 
the  outer  to  the  inner  side,  and  lying  under  the  aponeurotic  layer  over 
them;  but  beyond  the  opening  in  the  adductor  magnus  the  superficial 
branch,  i,  of  the  anastomotic  artery  runs  wit]j  it. 

One  or  two  branches  are  furnished  by  the  nerve: — an  occasional  offset, 
8,  communicates  with  the  internal  cutaneous  nerve;  and  a  large  patellar 
branch,  14,  pierces  the  sartorius  to  ramify  in  the  teguments  over  the  knee 
(p.  110). 

The  ileeiJ  set  of  hranclies  of  the  anterior  crural  are  furnished  to  mus- 
cles; they  supply  the  extensors  of  the  knee-joint,  and  the  sartorius  and 
pectineus. 

The  branch  to  the  sartorius,  3,  has  been  separated  from  its  muscles; 
oftentimes  an  offset  of  tlie  middle  cutaneous  enters  the  sartorius. 

The  nerve  to  the  rectus,  9,  has  been  cut  through  as  it  penetrates  the 
muscular  fibres. 

The  nerve  of  the  vastus  internus,  11,  pierces  the  fleshy  fibres  about 
the  middle  of  the  thigh.  As  it  is  about  to  enter  it  gives  a  slender  arti- 
cular branch,  13,  to  the  knee-joint,  which  runs  on  the  surface  of  the  vas- 
tus, covered  at  places  by  some  fleshy  fibres,  and  accompanies  lower  down 
the  anastomotic  artery  to  the  joint.  In  this  body  a  second  articular 
branch  issues  from  the  fleshy  fibres  nearer  the  knee. 

The  nerve  to  the  vastus  externus,  10,  will  be  described  with  the  fol- 
lowing Plate. 

The  nerves  to  the  pectineus,  2,  one  or  two  in  number,  arise  higher 


122  ILLUSTRATIONS   OF   DISSECTIONS. 

than  the  rest,  and  cross  beneath  the  femoral  vessels  to  be  distributed  to 
the  muscle:  for  their  ending,  see  Plate  xlvi. 

OMurator  nerve,  15.  A  small  part  of  this  nerve  is  included  in  the 
dissection,  but  its  distribution  is  visible  in  Plate  xlvii.,  with  which  it 
will  be  described. 


DESCRIPTION  OF  PLATE  XLVI. 


This  Illustration  shows  the  dissection  of  the  deep  muscles  of  the  fore 
and  outer  parts  of  the  thigh,  with  their  vessels  and  nerves. 

The  thigh  having  been  prepared  for  the  drawing  of  the  preceding 
Figure,  the  dissection  for  this  Plate  will  be  completed  by  cutting  through 
the  rectus  muscle,  and  removing  the  fat  from  the  branches  of  the  external 
circumflex  artery  and  anterior  crural  nerve.  With  the  handle  of  the 
scalpel  the  outer  vastus,  L,  may  be  separated  above  from  the  inner  vas- 
tus, F,  where  vessels  and  nerves  intervene;  and  the  thin  aponeurosis,  0, 
which  is  continued  from  their  common  tendon  over  the  knee-joint,  may 
be  cut  through  and  raised  to  the  sides  of  the  knee.  All  the  fascia  lata  on 
the  outer  part  of  the  thigh  is  to  be  removed,  except  a  narrow  slip  with 
the  insertion  of  the  tensor  vaginge  femoris. 

MUSCLES   OF  THE  FRONT  OF  THE  THIGH. 

The  chief  fleshy  mass  on  the  front  of  the  femur  is  formed  by  the  three 
parts  or  heads  of  the  extensor  of  the  knee-joint;  but  at  the  upper  and 
outer  parts  of  the  thigh  are  the  small  tensor  vaginae  femoris,  and  the 
gluteal  muscles. 


A.  Sartorius,  cut. 

B.  Gluteus  medius. 

C.  Tensor  vaginae  femoris. 

D.  Iliacus. 

E.  Rectus  femoris,  cut. 

F.  Vastus  internus. 

G.  Pectineus. 

H.  Adductor  longus. 


K.  Adductor  brevis. 
L.  Vastus  externus. 
M.  Gluteus  minimus. 
N.  Ligamentum  patellae. 
O.  Expansion  from  the  extensor  ten- 
don of  the  knee. 
P.  Tendon  of  the  extensor  cruris. 


PLATE  XLV 


1/  ^  ' 


'S% 


MUSCLES    OF    THE    FRONT    OF    THE    THIGH,  123 

The  tensor  vaginmfemoris,  Q,  is  a  small  muscle,  which  is  attached  by 
one  end  to  bone,  and  by  the  other  to  the  fascia  lata.  It  takes  origin  from 
tlie  upper  iliac  spinous  process,  from  the  contiguous  part  of  the  iliac  crest, 
and  from  half  the  notch  between  the  two  iliac  spinous  processes;  reaching 
downwards  at  the  outer  side  of  the  thigh,  it  is  inserted  into  the  fascia  lata 
where  the  upper  and  middle  thirds  meet. 

The  muscle  is  incased  in  strong  fascia,  and  is  placed  between  the  glu- 
teus medius,  B,  behind,  and  the  sartorius,  A,  and  rectus,  E,  in  front. 
Underneath  it  lies  the  upper  part  of  tlie  vastus  externus,  L,  and  the 
ascending  branches,  /,  of  the  external  circumflex  artery.     A  small  nerve, 

1,  and  arterial  offsets  enter  the  under  surface. 

The  muscle  can  abduct  the  thigh  from  the  other  limb,  and  make  tense 
the  fascia,  deriving  from  this  circumstance  the  name  tensor  of  the  fascia 
lata.  After  the  thigh  has  been  rotated  out  the  muscle  will  act  as  an  inter- 
nal rotator  of  the  femur. 

The  extensor  of  the  hnee  (triceps  extensor  cruris)  consists  of  three 
separate  parts  or  heads,  viz.,  rectus  femoris,  E,  vastus  internus,  F,  and 
vastus  externus,  L,  which  are  united  below  in  a  common  tendon. 

Rectus  femoris,  E  (Plate  xlv.).  This  spindle-shaped  muscle  forms 
the  middle  or  long  head  of  the  extensor.  It  arises  from  the  hip-bone  by 
two  tendinous  pieces: — one  is  attached  to  the  anterior  inferior  iliac  spin- 
ous process;  and  the  other,  longer  and  wider,  is  fixed  to  the  depression 
above  the  acetabulum.  Inferiorly  the  muscle  becomes  tendinous,  and 
blends  in  a  common  tendon  of  insertion,  P,  with  the  other  two  heads  of 
the  extensor. 

The  rectus  is  superficial  except  above,,  where  it  is  covered  by  the 
sartorius,  the  iliacus,  D,  and  the  gluteus  minimus,  M.  It  conceals 
branches  of  the  external  circumflex  artery,  e,  and  anterior  crural  nerve, 

2.  Some  of  the  fleshy  fibres  run  from  a  central  tendon  to  the  sides,  like 
the  feather  of  a  quill,  producing  the  arrangement  called  penniform. 

The  vastus  externus,  L,  or  outer  head  of  the  extensor,  arises  from  the 
upper  half  of  the  femur  by  a  piece  from  half  an  inch  to  an  inch  thick, 
which  is  limited  behind  by  the  following  points  of  the  bone,  viz.,  the 
outer  part  of  the  neck,  the  root  of  the  great  trochanter,  the  line  leading 
from  the  trochanter  to  the  linea  aspera,  the  upper  half  or  more  of  the 
linea  aspera;  and  it  arises  also  from  the  contiguous  external  intermus- 
cular septum.*  For  the  most  part  tendinous  above,  it  becomes  flesliy 
*  The  origin  of  the  muscle  here  specified  is  that  given  by  Cruveilhier  and 


124  ILLUSTRATIONS    OF    DISSECTIONS. 

lower  down,  and  the  fibres  end  inferiorly  in  the  common  tendon  of  in- 
sertion, some  joining  tlie  rectus  tendon  and  the  patella. 

The  upjDer  part  of  the  muscle  is  overlaid  by  the  rectus  and  tensor 
Taginse  femoris.  Beneath  this  vastus  lie  the  inner  vastus  in  part,  and 
branches  of  the  external  circumflex  artery  and  anterior  crural  nerve.  Its 
lower  tendon  occupies  the  under  surface,  and  extends  upwards  along  the 
anterior  or  free  edge  of  the  muscle. 

The  vastus  irdernus,  F,  constitutes  the  inner  or  large  head  of  the  ex- 
tensor. It  arises  from  the  shaft  of  the  femur  except  at  the  linea  aspera 
and  on  the  surfaces  behind  included  by  the  lines  prolonged  from  that 
ridge  of  bone  to  the  trochanters  in  one  direction  and  the  condyles  in  the 
other.*  Necessarily  the  fibres  cannot  be  fixed  where  the  outer  vastus 
takes  origin;  and  they  are  absent  from  the  ends  of  the  femur,  for  they 
reach  upwards  only  to  the  anterior  intertrochanteric  line,  and  cease  be- 
low near  the  articular  surface  of  the  knee-joint. 

Most  of  the  fleshy  fibres  are  received  on  the  superficial  aponeurosis, 
which  unites  with  the  other  heads  in  the  common  tendon  of  insertion, 
whilst  some  superficial  fibres  terminate  on  the  tendon  of  the  rectus  and 
on  the  patella. 

The  upper  part  of  the  muscle  is  deeply  placed  beneath  the  rectus  and 
sartorius,  and  vessels  and  nerves  (Plate  xlv.).  Along  the  inner  side  lie 
the  flexors  and  adductors  of  the  hip- joint  and  the  large  bloodvessels  of 
the  limb.  Towards  the  knee  the  muscle  becomes  prominent  and  makes 
a  larger  surface-swelling  than  the  vastus  externus  on  the  outer  side. 

Common  tendon  of  the  extensor,  P.  Above  the  joint  it  is  formed  by 
the  union  of  the  tendons  of  t|ie  three  heads;  and  it  is  continued  over  the 
knee-joint,  diminishing  in  width,  to  be  inserted  into  the  tubercle  of  the 
tibia,  and  into  an  inch  of  the  bone  below:  between  the  prominence  of  the 
tubercle  and  the  tendon  is  a  small  bursa.  Contained  in  the  tendon  is  the 
l^atella,  X,  which  comj)letely  divides  it  into  an  upper  and  a  lower  part: — 
The  upper  wide  part  intervenes  between  the  fleshy  fibres  and  the  base  of 

Theile,  and  is  not  so  extensive  as  that  assigned  to  it  in  English  anatomical  works: 
it  resembles  closely  the  attachment  of  the  outer  head  of  the  triceps  extensor 
bracliii. 

*  This  mass  is  described  commonly  as  consisting  of  two  muscles,  vastus  inter- 
nus  and  crureus.  Naturally  there  is  not  any  separation  between  the  two  on  the 
surface;  and  if  a  division  is  desired  the  mass  is  to  be  cut  through  longitudinally 
where  the  anterior  and  inner  surfaces  of  the  femur  meet. 


VESSELS    OF    THE    FRONT    OF    THE    THIGH. 


125 


the  patella;  and  the  louer,  narrower  part,  called  oftentimes  ligament  of 
the  patella,  fixes  the  apex  of  that  bone  to  the  tibia.  A  very  thin  layer  of 
tendinous  fibres  passes  over  the  cutaneous  surface  of  the  patella. 

An  aj)oneurotic  expansion,  0,  is  prolonged  from  the  upper  part  of  the 
tendon  over  the  patella  and  the  knee-joint,  and  is  fixed  into  the  bones  of 
the  leg.  On  the  knee  it  unites  with  the  fascia  lata,  and  with  prolonga- 
tions from  the  lateral  flexors  to  form  a  capsule  for  the  knee-joint. 

Subcmreus.  Under  the  extensor,  on  the  lower  fourth  of  the  femur, 
lie  some  scattered  fleshy  fibres,  arranged  frequently  in  an  outer  and  an 
inner  fasciculus,  which  are  inserted  inferiorly  into  the  synovial  membrane 
of  the  knee-joint. 

Action  of  the  extensor.  The  use  of  the  muscle  will  vary  with  the  fixed 
or  movable  condition  of  the  bones  of  the  limb  to  which  it  is  attached. 
If  the  tibia  is  free  to  be  moved  all  three  heads  will  advance  this  bone  on 
the  articular  surfaces  of  the  femur,  and  so  extend  the  knee-joint.  Should 
the  tibia  be  immovable,  as  in  rising  from  a  stooping  posture,  or  in  walk- 
ing, the  femur  and  jDelvis  will  be  brought  forwards  over  it.  By  the  con- 
tinued contraction  of  the  muscles,  after  those  bones  are  in  a  straight  line, 
the  body  will  be  supported  in  standing  by  the  action  of  the  rectus  on  the 
pelvis,  and  of  the  two  vasti  on  the  femur. 

The  fibres  of  the  subcrureus  draw  upwards  the  synovial  membrane  of 
the  knee-joint  as  the  tibia  and  femur  come  into  a  straight  line  in  exten- 
sion ;  and  they  are  supposed  to  remove  that  membrane  out  of  the  way  of 
pressure  by  the  patella. 


VESSELS  OF  THE  FRONT  OF  THE  THIGH. 

The  vessel  supplying  the  extensor  muscle  of  the  knee  is  the  external 
circumflex  branch  of  the  profunda  artery,  with  its  vein. 


a.  Femoral  arteiy, 

&.  Circumflex  iliac  artery. 

c.  Epigastric  artery. 

d.  Profunda  artery. 

e.  External  circumflex  artery. 


/.  Ascending  branch  of  circumflex. 
g.  Descending  branch. 
h.  Transverse  branch. 
i.   Femoral  vein. 


The  profunda  artery,  d,  runs  beneath  the  femoral  trunk,  and  distri- 
butes large  branches  in  the  thigh:  of  these  the  only  one  included  in  this 
Illustration  is  the  external  circumflex. 


126 


ILLUSTRATIONS    OF    DISSECTIONS. 


The  external  circumflex  artery,  e,  is  the  largest  branch  of  the  profunda, 
and  springs  near  the  beginning  of  that  trunk:  destined  for  the  outer  part 
of  the  thigh,  it  divides  into  three  chief  pieces  amongst  the  branches  of 
the  anterior  crural  nerve. 

The  ascending  branch,  /,  passes  under  the  sartorius,  rectus,  and  ten- 
sor vaginae  femoris  to  the  back  of  the  hip-bone,  where  it  supplies  the 
gluteal  muscles,  and  anastomoses  with  the  gluteal  artery:  it  furnishes 
nutritive  branches  to  the  muscles  amongst  which  it  passes. 

The  descending  branch,  g,  is  the  largest  of  the  three  pieces,  and 
divides  into  offsets  which  enter  the  deep  heads  of  the  extensor.  One  off- 
set courses  over  the  surface  of  the  vastus  externus  to  the  knee-joint  with 
a  small  nerve. 

The  transverse  branch,  Ji,  divided  into  two  or  more  offsets,  enters  be- 
neath the  vastus  externus,  and  piercing  that  muscle  anastomoses  with 
the  arteries  on  the  back  of  the  thigh. 

The  external  circumflex  vein  (Plate  xlv.  o)  has  the  same  general  dis- 
tribution as  the  artery,  and  joins  the  profunda  vein. 


NERVES  OF  THE  FRONT  OF  THE  THIGH. 

Two  nerves,  viz.,  a  branch  of  the  gluteal,  and  the  anterior  crural,  are 
supplied  to  the  muscles  described  in  this  Plate. 


1.  Nerve  to  tensor  vaginae  femoris. 

2.  Anterior  crural  nerve. 

3.  Branches  to  sartorius  and  rectus, 

cut. 

4.  Nerve  to  vastus  externus. 


5.  Upper  nerve  to  vastus  internus, 

6.  Lower  nerve  to  vastus  internus. 

7.  Internal  saphenous. 

8.  Nerve  to  the  pectineus. 


Ending  of  superior  gluteal  nerve,  1.  This  gluteal  nerve  is  distributed 
nearly  altogether  to  the  two  smaller  gluteal  muscles,  and  it  ends  ante- 
riorly, as  here  seen,  in  the  tensor  of  the  fascia  lata.  A  branch  of  the 
gluteal  artery  accompanies  the  nerve. 

Anterior  crural  nerve,  2.  The  deep  or  muscular  branches  of  this 
nerve  are  furnished  to  the  triceps  extensor,  the  sartorius,  and  to  one 
other  muscle,  the  pectineus. 

Branches  to  rectus  and  sartorius,  3,  3.  Each  enters  its  muscle  at  the 
upper  part;  they  were  cut  when  the  muscles  were  removed. 


PLATE  XLVI 


ADDUCTOJt   MUSCLES    OF   THE    HIP-JOINT.  127 

Branch  to  the  vastus  externus,  4.  This  is  a  large  nerve,  which 
enters  the  muscle  above  the  middle:  from  it  a  slender  articular  oifset  is 
prolonged  on  the  surface  of  the  vastus,  with  a  superficial  artery,  to  the 
capsule  of  the  knee-joint,  which  it  pierces. 

The  branches  to  the  vastus  internus  are  two  in  number.  The  upper 
one,  5,  is  supplied  to  the  fleshy  fibres  of  that  part  sometimes  named  cru- 
reus;  and  the  lower  branch,  6,  which  is  figured  in  the  preceding  Plate, 
belongs  to  the  inner  part  of  the  vastus  internus  and  to  the  inner  side  of 
the  knee-joint. 

Nerve  to  the  pectineus,  8.  This  branch  separates  from  the  trunk  of 
the  anterior  crural  near  Poupart's  ligament,  and  passes  beneath  the 
femoral  vessels  to  enter  the  pectineus  on  the  superficial  surface.  Often- 
times there  are  two  nerves  instead  of  one. 


DESCRIPTIOK  OF  PLATE  XLVII. 


In"  this  Illustration  the  dissection  of  the  deeper  adductor  muscles, 
with  the  profunda  artery  and  obturator  nerve,  is  exhibited. 

The  superficial  adductors  having  been  laid  bare  as  in  Plate  xlv.  ,  the 
pectineus  and  adductor  longus  are  to  be  cut  through;  and  after  removing 
the  greater  part  of  each  of  those  muscles,  the  deeper  adductors,  and  the 
ramifications  of  the  profunda  artery  and  obturator  nerve  are  to  be 
cleaned. 

ADDUCTOR  MUSCLES  OF  THE  HIP-JOINT. 

This  group  of  muscles  occupies  the  space  between  the  pelvis  and  the 
femur,  and  consists  of  three  adductors,  with  the  pectineus  and  gracilis: 
two  of  the  muscles,  viz.,  pectineus  and  adductor  longus,  are  represented 
in  Plate  xlv. 


A.  Sartorius. 

B.  Psoas  muscle. 

C.  Tensor  vaginae  femoris. 

D.  Iliacus. 


E.  Rectus  femoris,  cut. 

F.  Vastus  internus. 

G.  Pectineus,  cut. 

H.  Adductor  longus,  cut. 


128  ILLUSTRATIONS    OF    DISSECTIOJSTS. 


I.  Gracilis. 
J.  Adductor  magnus. 
K.  Adductor  brevis. 
L.  Vastus  externus. 


M.  Senii-membranosus. 

N.  Obturator  externus. 

O.  Semi-tendinosus. 

P.  Internal  lateral  licrament  of  knee. 


The  pectineus  (Gr,  Plate  xly.)  is  the  smallest  and  highest  of  the 
muscles  in  the  adductor  groujD.  It  has  a  fleshy  origin  from  the  ilio-pec- 
tineal  line  of  the  hip-bone,  and  from  the  smooth  triangular  surface  in 
front  of  that  line;  its  fibres  descend  and  are  inserted  by  means  of  a  thin 
tendon,  about  two  inches  wide,  behind  the  small  trochanter  of  the  femur, 
and  into  the  upper  part  of  the  line  leading  from  that  prominence  to  the 
linea  asp  era. 

The  muscle  is  in  contact  with  the  fascia,  and  forms  part  of  the  inner 
Taoundary  of  Scarpa's  space.  Beneath  it  lie  the  obturator  and  adductor 
TDrevis  muscles,  with  part  of  the  obturator  nerve.  Along  the  upper  border 
;is  placed  the  psoas  with  the  external  circumflex  vessels;  and  along  the 
.lower  is  the  adductor  longus. 

The  pectineus  will  ad  duct  and  raise  the  femur  if  this  bone  is  not  fixed; 
■and  it  will  take  part  with  the  rest  of  its  gi'oup  in  projecting  forwards  the 
thigh  in  walking.  When  the  femur  is  immovable,  as  in  standing,  it  will 
assist  in  balancing,  or  drawing  forwards  the  pelvis. 

The  adductor  longus  (H,  Plate  xlv.)  is  situate  on  the  same  level  as 
the  pectineus,  but  between  this  and  the  gracilis:  it  is  narrow  at  its  origin 
:from  the  pelvis,  but  becomes  wider  below.  Its  upper  tendon,  about  as 
-large  as  the  end  of  the  finger,  is  fixed  to  the  front  of  the  pubic  part  of  the 
hip-bone,  just  below  the  angle  formed  by  the  symphysis  and  the  pubic 
■crest;  ,and  the  lower  tendinous  end  is  inserted  into  the  inner  lip  of  the 
linea  aspera. 

Partly  subfascial,  this  adductor  is  covered  near  the  femur  by  the  sar- 
torius  and  the  femoral  vessels:  by  the  opposite  surface  it  touches  the 
adductor  brevis  and  magnus,  and  the  profunda  vessels  and  part  of  the 
obturator  nerve. 

The  muscle  assists  in  bringing  forwards  the  femur  in  walking;  and 
carrying  that  bone  towards  its  fellow,  it  will  be  chiefly  instrumental  in 
crossing  the  thighs.  If  the  femur  is  fixed,  as  in  standing,  the  muscle 
balances  with  others  the  pelvis  on  th-e  limb. 

The  gracilis,  I,  is  a  thin  tapering  muscle,  which  reaches  from  the 
pelvis  to  the  tibia.  It  arises  by  a  thin  tendon,  from  two  and  a  half  to 
three  inches  deep,  along  the  lower  border  of  the  hip-bone,  and  reaches 


ADDUCTOR    MUSCLES.  129 

upwards  half  way  along  tlie  symphysis.  At  the  lower  third  of  the  thigh 
it  ends  in  a  rounded  tendon,  and  is  inserted  into  the  inner  surface  of  the 
tibia,  beneath  the  sartorius,  A,  but  nearer  the  knee  than  the  semi-tend i- 
nosus,  0,  which  it  resembles  in  size  and  form. 

The  muscle  is  superficial,  and  its  connections  are  better  illustrated  in 
Plate  XLiY.  It  lies  against  the  adductor  brevis  and  magnus  as  far  as  the 
lower  third  of  the  thigh,  and  thence  against  the  semi-membranosus  as  it 
bounds  internally  the  popliteal  space.  Near  its  insertion  it  is  placed  on 
the  internal  lateral  ligament  of  the  knee-joint,  a  bursa  intervening;  and 
gives  an  expansion  to  join  the  fascia  of  the  leg. 

"With  the  limb  free  to  move  the  gracilis  will  draw  the  femur  towards 
the  other  thigh,  especially  after  abduction  of  it.  If  the  tibia  is  free  to 
move  the  muscle  will  bend  and  rotate  inwards  the  knee-joint;  and  when 
the  tibia  is  fixed  the  muscle  will  act  on  the  pelvis,  like  the  rest  of  the 
group. 

Adductor  brevis,  K.  Deeper  placed  than  the  muscles  before  described, 
it  arises  beneath  the  adductor  longus  from  the  fore  part  of  the  os  innom- 
inatum,  where  it  is  attached  outside  the  gracilis  for  a  distance  of  two 
inches.  Tlie  muscle  widens  below,  and  is  inserted  into  the  femur  behind 
the  pectineus,  and  into  the  line  prolonged  from  the  linea  aspera. 

It  is  concealed  above  by  the  pectineus  and  adductor  longus,  but  as 
these  separate  from  each  other  below  they  leave  a  large  part  of  the  muscle 
uncovered:  near  its  origin  it  is  crossed  by  the  superficial  part  of  the  ob- 
turator nerve,  and  at  its  insertion  by  the  profunda  vessels.  The  j)0ste- 
rior  surface  rests  on  the  adductor  magnus,  and  on  the  deep  piece  of  the 
obturator  nerve  and  the  accompanying  vessels.  Its  upper  border  touches 
the  obturator  and  psoas  muscles,  and  internal  circumflex  vessels. 

Its  action  is  similar  to  that  of  the  pectineus  and  adductor  longus;  for 
it  engages  in  adduction  of  the  femur;  in  the  projection  forwards  of  that 
bone  in  walking;  and  in  supporting  the  pelvis  in  standing. 

The  adductor  magnus,  J,  is  the  largest  muscle  in  the  group  of  adduc- 
tors, and  is  wide  and  fleshy  above,  but  narrow  and  tendinous  below.  It 
takes  origin  along  the  lower  border  of  the  hip-bone  between  the  symphysis 
and  the  ischial  tuberosity.  From,  the  pelvis  the  fibres  diverge  to  a  wide 
insertion  into  the  femur,  after  this  manner: — The  anterior  and  upper 
fibres  are  fixed  to  the  line  continued  from  the  great  trochanter  to  the 
linea  aspera,  to  the  linea  aspera  itself,  and  for  about  an  inch  to  the  ridge 
leading  from  that  crest  of  bone  to  the  inner  condyle;  whilst  tli^  hinder 


130  ILLUSTRATIONS    OF    DISSECTIONS. 

and  lower  fibres  end  in  a  strong  tendon,  and  are  attached  by  it  to  the 
inner  condyle  and  the  inner  condyloid  ridge. 

This  large  adductor  forms  a  triangular  partition  between  the  other 
adductor  muscles  and  the  hamstrings.  Its  upper  border  touches  the  ob- 
turator externus,  and  the  lower  is  overlaid  by  the  gracilis  and  sartorius. 
JS'ear  the  femur  the  profunda  vessels  lie  on  it;  and  the  muscle,  united 
with  the  other  adductors,  is  pierced  by  the  perforating  branches  of  those 
vessels.  At  the  lower  third  of  the  thigh  the  adductor  transmits  the  fe- 
moral artery  through  an  aperture,  Q,  which  is  tendinous  on  the  anterior 
and  fleshy  on  the  posterior  surface. 

This  muscle  acts  powerfully  as  an  adductor  of  the  thigh,  esjiecially  if 
the  limb  is  in  a  state  of  abduction,  as  in  riding.  When  the  limb  is  be- 
hind the  trunk  in  walking  the  great  adductor  will  bring  it  forwards;  but 
it  does  not  flex  the  hip-joint,  like  the  other  adductors.  In  standing  it 
will  prop  the  pelvis  with  its  companions. 

Psoas  and  iliacus.  These  muscles  are  separate  at  their  origin  in  the 
abdomen  (p.  58),  but  are  united  near  their  attachment  to  the  femur. 
The  psoas,  B,  becomes  tendinous  below,  and  is  inserted  into  the  small 
trochanter  of  the  femur.  The  iliacus,  D,  joins  by  some  fleshy  fibres  the 
outer  part  of  the  psoas  tendon,  but  the  rest  are  continued  to  the  femur, 
and  are  inserted  into  a  special  surface  in  front  of,  and  below  the  small 
trochanter. 

The  two  muscles  cover  the  hip-joint,  and  the  front  of  the  hip-bone 
between  the  iliac  crest  and  the  ilio-pubic  eminence:  a  large  bursa  sepa- 
rates the  psoas  from  the  joint:  and  a  smaller  one  intervenes  between  the 
iliacus  and  the  anterior  margin  of  the  bone.  On  the  psoas  lies  the  femo- 
ral artery;  and  between  the  two  muscles  the  anterior  crural  nerve  is 
imbedded.  Internally  are  placed  the  adductor  muscles  with  the  internal 
circumflex  vessels;  and  externally,  are  the  extensor  of  the  knee-joint, 
and  branches  of  the  external  circumflex  vessels. 

These  muscles  flex  the  hip-joint,  and  advance  the  femur  in  front  of 
the  trunk  in  making  a  step.  After  the  joint  is  flexed,  they  bring  forward 
the  small  trochanter,  and  so  rotate  out  the  femur;  their  action  on  the 
spinal  column  is  given  before  in  p.  59. 

Obturator  externus,  N.  The  origin  of  the  muscle  appears  with  the 
adductors,  and  the  insertion  with  the  muscles  of  the  buttock.  It  arises 
from  the  outer  surface  of  the  anterior  half  of  the  obturator  membrane, 
and  from  the  contiguous  part  of  the  hip-bone;  and  its  tendon,  which  is 


PROFUNDA    VESSELS. 


131 


directed  backwards  below  tbe  hip-joint,  is  inserted  into  the  pit  at  the 
root  of  the  great  trochanter. 

Tlie  muscle  acts  as  an  external  rotator  when  the  femur  hangs  and  is 
free  to  move;  but  its  fuller  action  on  that  bone  and  the  pelvis  will  be 
detailed  more  specially  with  the  anatomy  of  the  external  rotators. 


PROFUNDA  VESSELS  OF  THE  THIGH. 

The  large  profunda  artery  is  the  chief  nutritive  vessel  of  the  thigh; 
and  it  maintains  anastomoses  with  arteries  of  the  buttock  and  leg  when 
the  femoral  trunk  has  been  rendered  impervious  to  the  blood  by  ligature 
or  other  cause. 


a.  Femoral  artery. 

h.  Cix'cumflex  iliac  branch. 

c.  Epigastric  branch. 

d.  Profunda,  or  deep  femoral. 

e.  External  circumflex  branch. 
/.   Internal  circumflex  branch. 

g.  Muscular  branch  of  circumflex. 


h.  First  perforating  artery. 

i.    Second  perforating. 

/.     Tliird  perforating. 

k.    Continuation    of      profunda,    or 

fourth  perforating. 
I.    Anastomotic  branch. 


The  'profunda  artery,  d,  arises  from  the  femoral  trunk  about  one 
inch  and  a  half  below  Poupart's  ligament;  and  it  is  called  sometimes 
deep  femoral  from  its  position  to  the  parent  trunk.  It  courses  on  the 
inner  side  of  the  femur  parallel  to,  but  beneath  the  femoral  trunk,  as  far 
as  the  lower  third  of  the  thigh,  where  a  fine  branch  continues  it  onwards 
to  the  back  of  the  limb.  It  has  the  following  connections  with  muscles: 
— At  first  it  rests  on  the  iliacus,  and  appears  external  to  the  femoral 
artery  in  Scarpa's  triangular  space;  then  it  is  directed  down  and  in  under 
the  femoral  vessels,  lying  over  the  pectineus  and  adductor  brevis;  finally 
it  enters  beneath  the  adductor  longus,  and  ends  in  a  small  perforating 
branch  to  the  back  of  the  thigh.  Its  named  offsets  are  two  circumflex, 
and  four  perforating;  but  it  furnishes  also  large  unnamed  muscular  and 
anastomotic  branches. 

Circuwflex  Iranches.  Two  in  number,  they  wind  backwards,  one 
inside  and  the  other  outside  the  femur,  like  the  corresponding  arteries  in 
the  upper  limb,  and  communicate  at  the  back  of  the  thigh. 

The  external  circumflex,  e,  is  consumed  chiefly  in  the  extensor  muscle 


132  ILLUSTRATIONS    OF    DISSECTIONS. 

of  the  knee-joint  (p.  126),  and  its  ramifications  are  displayed  in  Plates 
XLVi.  and  lit. 

The  internal  circitmflex,  f,  bends  back  between  the  psoas,  B,  on  the 
one  side,  and  the  pectineus  and  adductor  brevis,  G  and  K,  on  the  other, 
and  divides  opposite  the  small  trochanter  into  two  terminal  pieces — an 
ascending  to  the  buttock,  and  a  transverse  to  the  back  of  the  thigh 

(Plate  L.). 

In  this  course  it  furnishes  an  articular  branch  to  the  hip-joint,  and 
muscular  offsets  to  the  obturator  externus  and  the  adductors:  the  largest 
of  these,  g,  passes  beneath  the  adductor  brevis,  supplying  it  and  the 
adductor  magnus,  and  accompanies  the  deep  part  of  the  obturator  nerve. 
■  Perforating  arteries.  Four  in  number,  they  pierce  the  aponeuroses 
of  the  adductor  muscles,  close  to  the  femur,  and  are  named  first,  second, 
etc.  After  reaching  the  back  of  the  thigh  they  supply  muscular  offsets 
to  the  biceps,  and  then  turn  round  the  femur  on  the  outside  to  end  in 
the  vastus  externus.     See  Plate  lit. 

The  -first  perforating,  li,  arises  opposite  the  lower  border  of  the  pecti- 
neus muscle,  and  perforates  the  adductor  brevis  and  magnus. 

The  second  perforating,  i,  leaves  the  trunk  half  way  down  the  adduc- 
tor brevis,  and  passes  through  the  same  adductors  as  the  preceding 
branch:  it  gives  an  offset  to  the  shaft  of  the  femur. 

The  tliird perforating,  j,  springs  from  the  profunda  at  the  lower  bor- 
der of  the  adductor  brevis,  and  is  transmitted  through  the  adductor 
magnus  to  its  destination. 

The  continuation  of  the  profunda  or  the  fourth  perforating,  Jc, 
pierces  the  great  adductor  muscle  near  the  opening  for  the  femoral 
artery. 

Muscular  Iranclies  of  the  profunda  enter  the  adductors;  but  the 
largest,  three  or  four  in  number,  pass  through  the  adductor  magnus  to 
end  in  the  hamstring  muscles  behind,  where  they  maintain  a  chain  of 
anastomoses  at  the  back  of  the  thigh  (Plate  lit.). 

The  profunda  vein  accompanies  the  artery  of  the  same  name,  and 
ends  above  in  the  femoral  vein.  In  this  course  it  is  superficial  to  its  artery, 
and  is  situated  between  the  trunks  of  the  femoral  and  profunda  arteries. 


■NERVES    OF    THE    FORE    PART. 


138 


NERVES  OF  THE  FRONT  OF  THE  THIGH. 

Two  nerves  are  included  in  this  dissection,  viz.,  the  anterior  crural, 
and  the  obturator;  the  first  nerve  and  its  branches  are  marked  by  the 
same  numbers  as  in  the  preceding  Figure. 


1.  Anterior    and  middle  cutaneous 

of  the  thigh,  cut. 

2.  Trunk  of  the  anterior  crural. 

3.  Nerve  of  the  rectus,  cut. 

4.  Nerve  to  the  vastus  externus. 

5.  Upper  nerve  to  vastus  internus. 

6.  Lower  nerve  to  vastus  internus. 

7.  Internal  saphenous  nerve. 

8.  Patellar  branch  of  saphenous. 


9.  Accessory  obturator  nerve. 

10.  Superficial  part  of  the  obturator. 

11.  Piece  to  the  femoral  artery. 

13.  Piece  to  join  the  internal  cutane- 
ous. 

13.  Deep  part  of  the  obturator. 

14.  Articular  branch  of  the  obturator 

to  the  knee-joint. 


Anterior  crural  nerve,  2.  The  view  of  the  nerve  in  this  Plate  is  very 
similar  to  that  in  the  i^receding  Figure:  its  description  has  been  given  at 
p.  120. 

The  obturator  nerve  ramifies  amongst  the  adductor  muscles.  Begin- 
ning in  the  lumbar  plexus  (p.  70),  it  leaves  the  pelvis  through  the  aper- 
ture in  the  upper  part  of  the  thyroid  foramen,  and  divides  into  two 
pieces,  superficial  and  deep,  as  its  escapes  from  the  cavity.  It  is  espe- 
cially the  nerve  of  the  adductors,  for  it  supplies  all  the  muscles  of  the 
group  except  the  pectineus;  and  it  furnishes  offsets  also  to  one  external 
rotator  of  the  hip,  viz.,  the  obturator  externus. 

The  superficial  part,  10,  ends  on  the  femoral  artery;  and  it  is  directed 
to  its  vessel  over  the  adductor  brevis,  but  beneath  the  pectineus  and 
adductor  longus.*  It  furnishes  branches  to  adductor  brevis  and  longus, 
and  to  the  gracilis;  and  it  communicates  by  the  offset,  12,  with  the  inter- 
nal cutaneous  branch  of  the  anterior  crural  nerve. 

Before  this  part  of  the  obturator  nerve  reaches  the  thigh  it  gives  an 
articular  branch  to  the  hip-joint;  and  beneath  the  pectineus  it  is  joined 
(sometimes)  by  a  communicating  offset  of  the  accessory  obturator  nerve,  9. 


*  In  the  Figure  the  nerve  appears  to  cross  over  the  ad.  longus,  but  this  is  occa- 
sioned by  the  muscle  being  cut,  and  the  nerve  being  displaced;  its  natural  posi- 
tion to  that  muscle  is  given  in  Plate  XLV. 


134 


ILLUSTRATIONS    OF    DISSECTIONS. 


The  deep  part  of  the  nerve,  13,  pierces  the  fibres  of  the  external  obtu- 
rator muscle  and  is  continued  into  the  thigh  beneath  the  adductor  brevis, 
furnishing  branches  to  this  muscle  and  the  adductor  magnus;  and  from 
the  ending  a  long  slender  articular  filament  is  continued  through  the 
adductor  magnus,  near  the  opening  for  the  femoral  vessels,  to  supply  the 
popliteal  artery  and  the  knee-joint  (Plate  lit.).  From  the  deep  part  of 
the  nerve  branches  are  supplied  to  the  external  obturator  muscle. 

The  accessory  obturator  nerve,  9,  is  a  small  branch  of  the  lumbar 
plexus,  which  is  but  rarely  present.  It  courses  from  the  abdomen  over 
the  front  of  the  hip-bone,  lying  close  inside  the  psoas  muscle;  it  then 
bends  outwards  under  the  pectineus,  where  it  joins  the  superficial  part  of 
the  obturator  nerve,  and  supplies  the  hip-joint.  When  it  is  large  it  fur- 
nishes occasionally  a  branch  to  the  pectineus. 


DESCRIPTION  OF  PLATE  XLVIII. 


In  this  Illustration  the  gluteus  maximus  may  be  observed  in  its  natu- 
ral position,  together  with  the  nerves  and  vessels  suj)erficial  to  it. 

The  skin  having  been  reflected,  as  in  the  Figure,  the  cutaneous  nerves 
and  vessels  will  be  found  in  the  fat  in  the  positions  indicated  in  the 
Plate.  After  the  examination  of  the  cutaneous  nerves  and  vessels  the 
gluteus  may  be  cleaned  by  beginning  at  the  upper  border  in  the  right 
limb,  and  at  the  lower  border  in  the  left  limb. 


CUTANEOUS  NERVES  AND  VESSELS  OF  THE  BUTTOCK. 

The  cutaneous  nerves  of  the  buttock  are  derived  from  many  sources, 
and  come  from  both  the  anterior  and  posterior  primary  trunks  of  the 
spinal  nerves.     Small  superficial  vessels  accompany  the  nerves. 


1.    Lateral  cutaneous  of  the  last  dor- 
sal nerve. 
1'.  Iliac     branch    of    ilio-hypogas- 
tric. 


2.  Lumbar    nerves    (posterior    pri- 

mary trunks). 

3.  Sacral  nerves  (posterior  primary 

trunks). 


PLATE  XLVil 


F -'^^i 


\ 


^\/ 


i£ 


S 


CUTANEOUS    NERVES    OF   THE    BUTTOCK. 


135 


4.  Sacral  nerves  (anterior  primary 

trunks). 

5.  Perineeal    branch   of  the  fourth 

sacral         (anterior        primary- 
trunk). 
6.   Recurrent    cutaneous    of     small 
sciatic. 


7.  Haemorrhoidal     branch      of     the 

pudic. 

8.  Inferior  pudendal  of    the    small 

sciatic. 

9.  Cutaneous  to  the    thigh    of    the 

small  sciatic. 
10.    Small  sciatic  nerve. 


The  lateral  cutaneous  of  the  last  dorsal  nerve,  1,  descends  from  tlie 
abdominal  wall  over  the  fore  part  of  the  iliac  crest,  and  continues  in  the 
fat  as  far  as  the  great  trochanter. 

The  iliac  hranch,  V ,  of  the  ilio-liypogastric  nerve  (p.  70)  crosses  the 
iliac  crest  close  to  the  bone,  and  commonly  behind  the  last  dorsal:  it  ex- 
tends to  the  fat  over  the  great  gluteal  muscle.  This  nerve  is  sometimes 
large,  and  takes  the  place  of  the  last  dorsal;  or  it  may  be  wanting. 

Posterior  lumlar  nerves,  2.  Cutaneous  branches  of  the  posterior 
primary  trunks  of  the  lumbar  nerves,  commonly  two  in  number,  enter 
the  teguments  at  the  anterior  border  of  the  erector  spinse  muscle,  and  are 
directed  downwards  over  the  gluteus  towards  the  great  trochanter. 

Posterior  sacral  nerves,  3.  The  posterior  primary  trunks  of  the  first 
three  sacral  nerves  pierce  the  fibres  of  the  gluteus  maximus,  after  uniting 
beneath  it  (Plate  l.).  Two  or  three  become  cutaneous,  and  bend  out- 
wards over  the  gluteus;  the  largest  is  opposite  the  end  of  the  sacrum. 

Atiterior  sacral  nerves,  4.  Branches  of  the  anterior  primary  trunks 
of  the  sacral  nerves  pierce  the  coccygeus  and  gluteus  maximus,  and  end  in 
the  neighboring  integuments. 

Two  other  small  nerves  of  the  perinaeum  issue  beneath  the  lower  edge 
of  the  gluteus.  One  is  the  peri7icBal  hrancli,  5,. of  the  fourth  sacral  nerve 
— and  the  other  is  the  inferior  hcemorrhoiclal  nerve,  7,  of  the  pudic.  Both 
of  these  have  been  noticed  in  page  15. 

The  small  sciatic  nerve,  10,  of  the  sacral  plexus  appears  at  the  lower 
border  of  the  great  gluteal  muscle,  and  is  then  continued  along  the  thigh 
(Plate  Lii.).  Near  the  lower  border  of  the  muscle  it  gives  two  sets  of 
cutaneous  branches — ascending  and  descending. 

The  ascending  or  recurrent  set,  which  are  marked  with  6,  wind  over 
the  edge  of  the  gluteus,  and  end  in  the  integuments  over  the  lower  part 
of  that  muscle. 

The  descending  set,  shown  by  the  number  9,  supply  the  integuments 
of  the  inner  part  of  the  thigh  below  the  buttock.     One  of  these,  8,  which 


136  ILLCSTRATIONS    OF    DISSECTIONS. 

is  larger  than  the  rest,  is  distributed  to  the  integuments  of  the  scrotum 
or  the  labium,  according  to  the  sex  (p.  20),  and  is  named  inferior  pu- 
dendal. 

The  external  cutaneous  of  the  thigh,  a  branch  of  the  lumbar  plexus 
(p.  70),  furnishes  offsets  to  the  fore  part  of  the  rogion  laid  bare. 

The  cutaneous  vessels,  lika  the  nerves,  are  derived  from  several  sources. 
Accompanying  the  last  dorsal  nerve,  1,  is  a  brunch  of  the  lowest  inter- 
costal artery;  and  running  with  the  ilio-hypogastric,  1',  is  a  small  branch 
of  a  lumbar  artery.  With  the  lumbar  nerves,  2,  are  offsets  of  the  poste- 
rior branches  of  the  lumbar  art'ries;  and  with  the  sacral  nerves,  3  and  4, 
are  branches  of  the  sciatic  artery.  The  offsets  of  the  small  sciatic  nerve, 
10,  have,  as  their  companions,  ramifications  of  the  sciatic  artery. 
Through  the  upper  part  of  the  gluteus  branches  of  the  gluteal  artery 
penetrate;  and  through  the  lower  part,  the  branches  of  the  sciatic  artery. 
At  the  upper  border  of  the  gluteus  appear  offsets  also  of  the  gluteal  artery: 
and  small  branches  of  the  external  circumflex  of  the  profunda  perforate 
the  fascia  lata  over  the  great  trochanter. 


I^IUSCLES  OF  THE  BUTTOCK. 

Only  the  great  gluteal  muscle  is  dissected  in  this  stage,  though  two 
other  glutei  cover  the  hip-bone;  and  one,  the  gluteus  medius,  shows 
through  the  fascia  in  the  Plate.  Issuing  bneath  the  gluteus  maximus 
are  the  hamstring  muscles  of  the  thigh. 


A.  Gluteus  maximus. 

B.  Gluteus  medius,  covered  by  fas- 

cia. 

C.  Fascia  lata  of  the  tliigh. 


D.  Biceps  flexor  cruris 

E.  Semitendinosus. 

F.  Semimembranosus, 

G.  Adductor  magnus. 


The  gluteus  maximus,  A,  reaches  from  the  pelvis  to  the  femur,  and 
resembles  the  deltoid  muscle  of  the  upper  limb  in  its  position,  and  in  the 
coarseness  of  its  fibres. 

The  pelvic  attachment,  or  the  origin,  is  fixed,  from  above  down,  to 
the  posterior  third  of  the  crest  and  the  contiguous  part  of  the  hip-bone, 
to  the  tendon  of  the  multifidus  spinas,  to  the  last  piece  of  the  sacrum, 
and  to  the  side  of  the  coccyx  and  the  great  sacro-sciatie  ligament.  From 
this  attachment  the  coarse  bundles  of  fibres  are  directed  downwards  and 


PLATE  XLIX. 


'f 


GLUTEUS   MAXIMUS    MUSCLE.  137 

outwards,  and  becoming  tendinous  are  inserted  into  the  fascia  lata  and 
the  femur — about  the  upper  two-thirds  joining  the  fuseia,  and  tlie  rest 
the  bone.  The  precise  insertion  is  made  evident  in  Plate  lil,  where  the 
muscle  is  partly  cut  through  and  reflected. 

This  gluteus  is  covered  by  the  fascia  lata  and  teguments;  and  it  is  in 
contact  by  the  deep  surface  with  the  parts  displayed  in  Plate  xlix.  Its 
upper  border,  the  shortest,  is  crossed  by  cutaneous  vessels  and  nerves,  and 
rests  on  the  gluteus  medius;  whilst  the  lower  border  forms  part  of  the 
ischio-rectal  fossa,  and  lies  over  the  adductor  magnus  and  the  hamstring 
muscles.  Eound  the  lower  border  wind  branches  of  the  small  sciatic 
nerve  with  their  accompanpng  vessels. 

If  the  femur  is  immovable  the  muscles  of  both  sides  will  assist  in  bal- 
ancing the  pelvis  on  the  thigh-bones,  as  in  standing;  and  if  the  pelvis  is 
bent  forward,  as  in  stooping  to  the  ground,  the  large  glutei  will  act  pow- 
erfully in  bringing  the  trunk  into  the  erect  position.  In  rising  from  the 
sitting  to  the  upright  posture,  these  musc'es  are  chiefly  active,  becoming 
extensors  of  the  hip- joints.  In  standing  on  one  leg,  say  the  right,  the 
trunk  "will  be  rotated  on  its  bony  prop,  so  as  to  have  the  face  turned  to 
the  left  side. 

If  the  thigh-bone  is  free  to  move,  the  muscle  will  rotate  out  the 
femur,  and  will  then  abduct,  and  carry  back  that  bone  so  as  to  extend 
the  hip-joint. 


DESCRIPTION  OF  PLATE  XLIX. 


The  second  stage  of  the  Dissection  of  the  buttock  is  depicted  in  this 
Figl^re. 

The  view  here  given  may  be  obtained  by  cutting  vertically  through 
the  gluteus  maximus  near  the  pelvic  attachment,  and  removing  carefully 
all  the  fat  from  the  underlying  muscles,  vessels,  and  nerves.  On  the  fore 
part  of  the  gluteus  medius  the  fascia  lata  has  been  left. 

MUSCLES  OF  THE  BUTTOCK. 

Two  groups  of  muscles  occupy  the  back  of  the  pelvis,  viz.,  the  glutei 
or  abductors  of  the  hip,  and  the  external  rotators  of  the  same  joint. 


138  ILLUSTRATIONS    OF    DISSECTIONS. 


A.  Gluteus  maximus,  cut. 

B.  Gluteus  medius. 

C.  Pyriformis. 

D.  Gluteus  minimus. 

E.  Gemellus  superior. 

F.  Obturator  intemus. 

G.  Gemellus  inferior. 
H.  Obturator  externus. 
I.     Quadratus  femoris. 


J.    Adductor  magnus. 

L.  Semitendinosus.  . 

N.  Biceps  cruris. 

O.  Semimembranosus. 

P.  Vastus  externus. 

Q.  Tensor  vaginse  femoris. 

R.  Great  sacro-sciatic  ligament. 

S.    Fascia  lata  on  the  gluteus. 


The  gluteus  medius,  B,  is  placed  farther  forwards  than  the  glutens 
maximns,  and  the  fibres  converge  to  the  top  of  the  trochanter.  It  arises 
from  the  outer  surface  of  the  os  innominatum  between  the  crest  and  the 
upper  curved  line,  except  behind  where  the  gluteus  maximus  is  attached, 
-extending  nearly  to  the  hinder  border  of  the  bone  ;  and  the  superficial 
Jbres  are  attached  to  the  fascia  lata.  The  muscle  is  inserted  below 
.across  the  outer  surface  of  the  great  trochanter  from  the  tip  to  the  root. 

The  muscle  is  in  part  subcutaneous,  and  is  in  j)art  covered  by  the 
^gluteus  maximus.  Its  anterior  border  touches  the  tensor  fasciae  latae, 
Q ;  and  the  hinder  border,  which  is  contiguous  to  the  pyriformis,  near 
the  pelvis,  overlays  this  muscle  near  the  femur.  Between  it  and  the 
pyriformis  are  seen  the  superficial  part  of  the  gluteal  artery  and  the 
.superior  gluteal  nerve. 

The  action  of  the  muscle  will  vary  with  the  state  of  the  bones  as  to 
ifixedness  or  mobility. 

Should  the  femur  be  free  to  be  moved  the  muscle  will  abduct  it  from 
its  fellow.  If  the  bone  is  hanging  the  anterior  and  lower  fibres  will 
rotate  it  inwards.  In  the  beginning  of  a  step  in  walking,  the  fore  part 
of  the  muscle  acts  with  the  smallest  gluteus  in  bringing  forwards  the 
hinder  limb  until  it  comes  into  a  line  with  the  trunk. 

When  both  legs  are  fixed,  as  in  standing,  this  and  the  small  gluteus 
will  aid  in  balancing  the  pelvis  on  the  thighbones.  When  the  body  is 
propped  on  one  leg,  the  two  smaller  gluteal  muscles  act  powerfully  in 
keeping  the  hip-bone  fixed  ;  and  in  walking  the  same  glutei  muscles 
assist  in  balancing  the  trunk  over  the  supporting  limb.  The  anterior 
fibres  alone  acting  will  turn  the  face  to  the  same  side. 

The  gluteus  minimus,  D,  is  covered  by  the  preceding,  and  is  attached 
to  the  pelvis  and  the  thigh-bone,  like  the  medius  ;  it  resembles  this  mus- 
-cle  in  its  action,  and  it  will  be  described  with  the  following  Plate. 


EXTERNAL    ROTATOR   MUSCLES.  139 

External  rotators  of  the  hip- joint.  This  group  consists  of  six  muscles, 
viz.,  pyriformis,  obturator  internus  and  gemelli,  quadratus  femoris,  and 
obturator  extcrnus.  All  are  placed  at  the  back  of  the  joint,  and  are 
directed  almost  transversely  from  the  pelvis  to  the  top  of  the  femur. 

The  pyriformis,  C,  arises  inside  the  pelvis  from  the  front  of  the 
sacrum  (p.  74) ;  and  as  it  issues  from  that  cavity  by  the  great  sacro- 
sciatic  notch  it  has  a  further  fleshy  attachment  to  the  edge  of  the  hip- 
bone, and  to  the  great  sacro-sciatic  ligament,  R.  Outside  the  pelvis  the 
muscle  is  inserted  by  a  narrow  tendon  into  the  top  of  the  great  tro- 
chanter between  the  two  smaller  glutei. 

The  part  of  the  muscle  in  the  buttock  is  concealed  by  the  gluteus 
maximus,  and  by  the  gluteus  medius  in  part ;  and  rests  on  the  gluteus 
minimus,  which  separates  it  from  the  hijD-joint.  The  upper  edge  lies 
along  the  gluteus  medius,  and  the  lower  is  near  the  upper  gemellus,  E. ' 
As  it  escapes  from  the  pelvis  it  divides  into  two  the  great  sacro-sciatic 
notch  :  through  the  upper  part  issue  the  gluteal  vessels,  and  the  upper 
gluteal  nerve  ;  and  through  the  lower  come  the  sciatic  and  pudic  vessels 
and  nerves. 

Should  the  thigh-bone  hang  loosely,  the  muscle  will  draw  backwards 
the  great  trochanter,  and  give  rise  to  rotation  outwards  ;  but  should  the 
hip-joint  be  bent,  it  will  abduct  the  femur  from  the  other  limb.  Sup- 
posing the  limb  fixed,  as  in  standing,  the  pyriformis  will  help  to  balance 
the  pelvis  ;  and  in  rising  from  a  stooping  posture  it  will  assist  in  erecting 
the  trunk.  In  standing  on  one  leg,  say  the  right,  it  will  rotate  the 
trunk,  turning  the  face  to  the  opposite  side. 

The  oMurator  internus,  F,  arises  inside  the  pelvis,  like  the  pyri- 
formis, and  is  attached  to  nearly  the  whole  inner  surface  of  the  obtura- 
tor membrane,  and  to  the  greater  part  of  the  inner  surface  of  the  hip- 
bone behind  the  thyroid  hole.  The  muscle  appears  through  the  small 
sacro-sciatic  notch,  and  passes  over  the  back  of  the  hip-joint  to  be 
inserted  into  the  great  trochanter,  in  front  of  the  pyriformis,  and  into 
the  contiguous  part  of  the  neck  of  the  femur. 

Outside  the  pelvis  the  small  gemelli  muscles  lie  along  the  sides  of  the 
obturator  ;  the  whole  is  covered  by  the  gluteus  maximus,  and  is  crossed 
by  the  sciatic  vessels  and  nerves  :  underneath  is  the  capsule  of  the  hip- 
joint — a  bursa  intervening.  In  the  sacro-sciatic  notch,  the  pudic  vessels 
with  nerves  lie  on  the  muscle  ;  and  the  under  surface,  which  is  tendin- 


140  ILLUSTRATIONS    OF    DISSECTIONS. 

ous  and  diyided  into  pieces  as  it  rests  on  the  bone,  is  lubricated  by  a 
synovial  membrane. 

This  muscle  being  almost  parallel  to  the  pyriformis,  its  action  is  sim- 
ilar on  the  pendent  and  elevated  femur ;  and  on  the  pelvis  when  sup- 
ported on  both  legs  or  on  one.  During  walking  it  and  the  other  mem- 
bers of  its  group  assist  the  gluteus  medius  and  minimus  in  fixing  the 
pelvis  on  the  supporting  limb  ;  and  when  the  limb  is  swung  forwards,  it 
and  the  other  rotators  will  keep  the  foot  straight. 

The  gemellus  superior,  E,  arises  from  the  outer  and  lower  part  of  the 
ischial  spine,  and  is  inserted  with  the  obturator  internus,  which  it  joins. 
The  muscle  lies  above  the  obturator  internus,  and  is  smaller  than  its 
fellow  :  it  is  often  absent. 

The  gemellus  inferior,  G,  is  in  contact  with  the  lower  border  of  the 
obturator  internus,  and  is  much  larger  than  the  upper  gemellus.  It 
arises  from' the  lower  edge  of  the  groove  in  the  hip-bone  for  the  obtura- 
tor internus ;  and  it  is  inserted  into  the  trochanter  of  the  femur  with 
the  obturator  muscle. 

These  muscles  have  the  same  connections  as  the  extra-pelvic  part 
of  the  obturator  internus,  to  which  they  seem  to  be  accessory  heads  of 
attachment.  The  upper  intervenes  between  the  obturator  and  the  pyri- 
formis and  gluteus  minimus,  and  the  lower  separates  the  obturator  fi'om 
the  quadratus  femoris  and  obturator  externus.  Near  the  pelvis  the 
edges  are  applied  together  to  form  a  kind  of  groove,  Avhich  contains  the 
obturator,  but  near  the  femur  they  cover  the  tendon  of  that  muscle. 

They  act  on  the  thigh-bone  like  the  obturator  internus,  rotating  out 
when  the  limb  is  hanging,  and  abducting  when  the  femur  is  bent  on  the 
trunk.  In  standing  on  both  legs,  on  one  leg,  and  in  walking,  they  will 
also  assist  the  obturator,  though  their  power  will  be  but  small. 

The  oMurator  externus,  H,  appears  as  a  tendon  between  the  inferior 
gemellus  and  quadratus  femoris.  Its  origin  opposite  the  obturator 
internus  from  the  outer  pa¥t  of  the  membrane  of  the  same  name,  and  in 
part  from  the  pelvis,  is  indicated  in  Plate  xlvii.  ;  and  the  buttock  part 
of  the  muscle  will  be  illustrated  in  the  next  Plate.     • 

The  quadratus  femoris,  I,  is  thin  and  fleshy,  and  arises  from  the 
outer  border  of  the  tuber  ischii,  external  to  the  semimembranosus  and 
the  adductor  magnus.  Its  fibres  form  a  squarish  layer,  from  two  to 
■three  inches  wide,  which  is  mserted  into  a  tubercle  in  the  posterior 
inter-trochanteric  line,  and  vertically  into  the  upper  end  of  the  femur 


ARTERIES  OF  THE  BUTTOCK. 


141 


for  two  inches:  the  line  of  attachment  is  sometimes  called  linea  quad- 
rat!. 

Covered  by  the  same  parts  as  the  other  rotators,  it  is  also  concealed 
at  its  origin  by  the  hamstring  muscles.  Underneath  it  is  the  obturator 
externus  with  the  hip-joint.  By  the  upper  border  it  touches  the  inferior 
gemellus  and  obturator  externus  ;  and  by  the  lower  it  is  in  contact  with 
the  adductor  magnus — a  piece  of  the  internal  circumflex  artery  with  its 
veins  issuing  between  the  two. 

This  muscle  will  assist,  though  but  feebly,  the  pyriformis  and  obtu- 
rators in  rotating  out  the  hanging'limb  ;  in  abducting  the  bent  limb  ;  in 
balancing  the  pelvis  in  standing  on  both  legs,  or  on  one  ;  and  in  rotating 
the  face  to  the  opposite  side  when  the  trunk  is  supported  on  one  leg. 

Hamstrings  and.  adductor  magnus.  The  upper  ends  of  the  three  flex- 
ors of  the  knee-joint  (hamstrings)  are  laid  bare  at  their  attachment 
to  the  ischial  tuberosity  ;  they  consist  of  semitendinosus,  L,  biceps,  N, 
and  semimembranosus,  0,  and  they  are  more  fully  seen  in  Plate  lii. 

Parts  of  the  origin  and  insertion  of  the  adductor  magnus,  which  were 
not  visible  in  the  former  view  of  the  muscle  (Plate  xlvii.),  are  now  de- 
nuded. Internal  to  the  hamstrings  may  be  seen  the  origin  from  the 
ischial  tuberosity;  and  external  to  those  muscles  is  the  wide  expanded 
part,  which  is  inserted  into  the  femur  in  a  line  with  the  quadratus 
femoris,  and  in  the  attachment  side  of  the  gluteus  maximus. 


ARTERIES   OF  THE  BUTTOCK. 

Most  of  the  arteries  of  the  buttock  belong  to  the  set  of  external  parie- 
tal branches  of  the  internal  iliac  (p.  67):  they  are  the  gluteal,  sciatic, 
and  pudic,  which  issue  from  the  pelvis  by  the  great  sacro-sciatic  notch. 
Branches  of  the  profunda  artery  appear  also  in  the  lower  part  of  the 
resfion  dissected. 


a.  Superficial  part  of  the  gluteal  ar- 
tery. 
h.  Pudic  artery. 

c.  Trunk  of  the  sciatic. 

d.  Coccygeal  branch  of    the   scia- 

tic. 


e.  Muscular  and  anastoniatic  branch 
of  the  sciatic. 
/.  Continuation  of  the  sciatic. 
g.  Branch  to  great  sciatic  nerve. 
h.  Branch  of  internal  circumflex. 
i.   Ending  of  first  perforating  artery. 


The  gluteal  artery  comes  through  the  great  sacro-sciatic  iwtch  above 


14:2  ILLUSTRATIONS    OF   DISSECTIONS. 

the  pyriformis,  and  supplies  the  gluteal  muscles.  It  divides  at  once  into 
a  superficial  and  a  deep  piece,  and  the  latter  of  these  will  be  contained  in 
the  next  Plate. 

The  superficial  part  a,  sends  off  many  branches  to  the  under  surface 
of  the  gluteus  maximus.  One  or  two  small  branches  run  inwards  and 
backwards  through  the  great  sacro- sciatic  ligament  to  the  integuments, 
and  send  deeper  offsets  to  the  muscle  over  the  back  of  the  sacrum. 

The  j'J^fc?ic  ai'tery,  1),  appears  in  the  buttock  for  a  very  short  distance: 
it  leaves  the  pelvis  through  the  great  sacro-sciatic  notch,  below  the  pyri- 
formis,  and  then  winds  over  the  ischial  spine  by  the  side  of  the  nerve  of 
the  same  name,  to  enter  the  perineum  through  the  small  sacro-sciatic  notch. 

The  sciatic  artery,  c,  escapes  with  the  pudic  and  sciatic  vessels  and 
nerves  through  the  great  sacro-sciatic  notch,  and  is  accompanied  by  cu- 
taneous offsets  of  tlie  small  sciatic  nerve.  It  supplies  the  joart  of  the 
buttock  below  the  gluteal  artery,  and  furnishes  the  following  branches: — 

The  coccygeal  hrancli,  d,  pierces  the  great  sacro-sciatic  ligament,  and 
supplies  the  gluteus  maximus:  one  of  its  branches  enters  that  muscle, 
and  accompanies  the  chief  cutaneous  offset  of  the  sacral  nerves;  whilst 
others  ramify  on  the  back  of  the  sacrum  and  coccyx. 

Muscular  and  anastomotic  hrancli,  e.  This  artery  varies  much  in 
size,  and  passes  transversely  outwards  to  the  root  of  the  great  trochanter. 
It  supplies  largely  the  gluteus  maximus,  and  ends  at  the  spot  mentioned 
by  anastomosing  with  the  gluteal  and  internal  circumflex  arteries. 

Nerve  branches.  A  small  artery,  g,  enters  the  trunk  of  the  great  sci- 
atic nerve,  and  is  called  "comes  nervi  ischiadici."  And  the  continuation 
of  the  artery,  /,  accompanies  the  smaller  sciatic  nerve,  branching  like  it 
to  be  distributed  with  the  several  offsets  of  the  nerve. 

Muscular  hranclies,  many  of  which  were  cut  in  the  dissection,  enter 
the  under  surface  of  the  great  gluteus,  and  the  loAver  external  rotator 
muscles;  and  the  artery  to  the  quadratus  femoris  runs  to  its  muscle  with 
the  nerve,  5,  beneath  the  gemelli  and  internal  obturator. 

The  internal  circumflex  artery  of  the  profunda  (Plate  L.)  divides  into 
two  beneath  the  quadratus:  the  branch,  h,  to  the  thigh  issues  between 
the  contiguous  borders  of  the  quadratus  and  adductor  magnus,  and  is 
distributed  to  the  hamstrings. 

First  perforating  artery.  This  branch  of  the  profunda  pierces  the 
adductor  magnus,  and  supplying  the  gluteus  maximus  and  the  biceps 
muscle,  N,  ends  in  the  vastus  externus. 


•NEKVK8    OF    THE    BUTTOCK. 


143 


NERVES  OF  THE  BUTTOCK. 

Most  of  the  nerves  included  in  this  dissection  are  branches  of  the 
sacral  plexus,  and  appear  at  the  lower  border  of  the  pyriformis,  where 
the  plexus  ends:  they  may  be  arranged  into  branches  to  the  limb,  to  the 
perineum,  and  to  some  external  rotator  muscles.  By  the  side  of  the  glu- 
teal artery  is  the  superior  gluteal  nerve,  which  is  not  derived  from  the 
plexus;  and  on  the  great  sacro-sciatic  ligament  lies  a  branch  of  the  sacral 
nerves. 


1.  Cutaneous  branch  of  the  sacral 

nerves. 

2.  Pudic  nerve. 

3.  Nerve  to  the  obturator  internus. 

4.  Branch  to  the  upper  gemellus. 

5.  Branch  to  the  quadratus  f emoris. 

6.  Upper  branches  to  the  gluteus 

niaxinius. 

7.  Small  sciatic  nerve. 

8.  Lower    branches    to  the  gluteus 

maximus. 


9.  Inferior  pudendal  nerve. 

10.  Cutaneous  of   the  buttock    and 

inner  part  of  the  thigh. 

11.  Great  sciatic  nerve. 

12.  Muscular    branch    of    the    great 

sciatic. 

13.  Superior  gluteal  nerve. 

14.  Iliac  branch  of  ilio-hypogastric. 
ft  Cutaneous  of  the  posterior  trunks 

of  the  lumbar  nerves. 


The  small  sciatic  nerve,  7,  is  chiefly  a  cutaneous  nerve  of  the  buttock, 
scrotum,  and  back  of  the  limb,  for  only  one  muscle  (gluteus  maximus) 
receives  branches  from  it.  It  begins  by  two  or  more  pieces  in  the  lower 
part  of  the  sacral  plexus,  and  takes  the  course  of  the  sciatic  artery  over 
some  of  the  external  rotators,  as  far  as  the  lower  border  of  the  gluteus 
maximus:  here  the  nerve  furnishes  many  branches  (Plate  xlviii.),  and 
is  continued  beneath  the  fascia  of  the  thigh  with  a  branch  of  artery  to  the 
integuments  of  the  calf  of  the  leg.     Its  offsets  are  these: — 

Mu.scular  or  gluteal  branches,  8,  enter  the  lower  part  of  the  gluteus 
maximus:  they  are  called  inferior  gluteal,  to  distinguish  them  from  the 
branches  of  the  superior  gluteal  nerve,  for  the  smaller  glutei  muscles. 

The  inferior  pudendal,  9,  Avinds  beneath  the  fascia  lata,  and  below 
the  ischial  tuberosity,  near  which  it  becomes  cutaneous  to  end  in  the 
scrotum  or  the  labium  (Plate  xxxi.). 

Cutantous  branches  of  the  hut  lock  and  thigh,  10.  The  branches  of 
the  buttock  run  backwards  over  the  gluteus  maximus,  and  are  better 


144  ILLU3TBATI0XS    OF    DISSECTIONS. 

shown  in  Plate  xltiii.  The  thigh- branches  are  inclined  downwards  and 
inwards,  and  piercing  the  fascia  lata,  end  in  the  integument  of  the  upper 
third  of  the  thigh  on  the  inner  aspect. 

The  grecit  sciatic,  11,  is  the  largest  nerve  in  the  body;  and  in  it  the 
sacral  plexus  terminates.  In  its  course  to  the  back  of  the  thigh  it  is 
j^laced  in  the  hollow  between  the  great  trochanter  and  the  ischial  tuber- 
osity, lying  on  the  external  rotators  below  the  pyriformis;  and  it  is  con- 
cealed by  the  gluteus  maximus  till  it  reaches  the  hamstrings.  As  the 
nerve  is  about  to  leave  the  region  of  the  buttock  a  branch  for  the  ham- 
string muscles  is  detached  from  it,  wliose  distribution  will  appear  in 
Plate  Lii. 

Tlie  pudic  nerve,  2,  turns  over  the  small  sacro-sciatic  ligament  by  the 
side  of  the  artery  of  the  same  name,  and  gains  the  perinaeal  space  through 
the  small  sacro-sciatic  notch.  Its  further  progress  is  given  in  the  Plates 
of  the  perinseum. 

Muscular  hranclies  of  the  sacral  ])lexus  supply  the  gluteus  maximuSj 
and  all  the  external  rotators  except  the  obturator  externus. 

The  branches  to  the  gluteus,  6,  have  been  cut  across  as  they  pierce 
the  muscular  fibres:  these  are  known  as  inferior  gluteal,  like  the  branches 
of  the  small  sciatic  to  the  same  muscle,  and  penetrate  the  upper  fleshy 
fibres. 

The  branch  to  the  obturator  internus,  3,  with  its  artery,  accompanies 
the  pudic  vessels  through  the  small  sacro-sciatic  notch,  and  soon  sinks 
into  the  fleshy  fibres. 

The  branch  to  the  upper  gemellus,  4,  is  sometimes  very  fine;  a  con- 
siderable difference  in  its  size  is  manifest  in  the  following  Plate  which 
was  drawn  from  another  body. 

The  branch  to  the  inferior  gemellus  and  quadratus,  5,  is  a  slender 
nerve,  which  runs  with  a  small  artery  beneath  the  gemeUi  and  obturator 
internus. 


PLATE  L 


.^ 


^yf 


\ 


DEEP    MUSCLES    OF   THE    BUTrOCK. 


145 


BESCRIPTIOX  OF  PLATE  L 


Ix  this  Figure  the  third  stage  in  the  dissection  of  tlie  buttock  is  rep- 
resented. 

Supposing  the  second  stage  of  the  dissection  to  have  been  carried  out 
as  in  the  preceding  Plate,  the  tliird  stage  will  be  arrived  at  by  removing 
the  glutens  medius,  and  by  cutting  through  and  reflecting  the  obturatur 
internus  and  quadrat  us  femoris.  On  taking  away  a  superficial  stratum 
of  the  great  sacro-sciatic  ligament  the  sacral  nerves  will  come  into  sight. 

The  small  sciatic  nerve  and  the  sciatic  artery  were  cut  away,  and  all 
the  veins  were  removed  with  the  view  of  rendering  the  connections  less 
complicated. 


DEEP  MUSCLES  OF  THE  BUTTOCK. 

Two  muscles,  the  gluteus  minimus  and  obturator  externus,  come 
under  notice  for  the  first  time;  but  most  of  the  others  have  been  demon- 
strated in  the  preceding  Plate,  though  some  points  in  their  anatomy 
receive  here  further  illustration. 


A.  Cut  ends  of  the  gluteus  maxi- 

mus. 

B.  Insertion  of  the  gluteus  medius. 

C.  Gluteus  minimus. 

D.  Tensor  vaginae  femoris. 

E.  Pyriformis. 

F.  Upper  gemellus. 

G.  Obturator  internus,  cut. 
H.  Lower  gemellus. 

I.  Cut  ends  of  the  quadratus  femo- 


J.  Obturator  externus. 

K.  Insertion  of  psoas  magnus. 

L.  Insertion  of  adductor  magnus. 

N.  Vastus  externus. 

O.  Semimembranosus. 

P.  Biceps  cruris  (long  head). 

R.  Semitendinosus. 

T.  Origin  of  adductor  magnus. 

U.  Great  sacro-sciatic  ligament. 

Y.  SmaU  sacro-sciatic  ligament. 


The  gluteus  minimus,  C,  is  somewhat   pyramidal   in   form,  and  is 

attached  to  the  hip-bone  and  femur,  like  the  gluteus  medius,  beneath 
10 


146  ILLUSTRATIONS    OF   DISSECTIONS. 

which  it  lies.  It  arises  from  the  space  between  the  two  curved  lines  on 
the  back  of  the  hip-bone,  and  extends  backwards  to  the  line  of  union  of 
the  iliac  and  ischial  portions  of  that  bone.  From  this  attachment  the 
fibres  are  directed  downwards,  converging  to  a  tendon,  which  is  inserted 
along  the  fore  part  of  the  great  trochanter,  and  blends  inferiorly  with  the 
tendon  of  the  gluteus  medius.  Some  of  the  deeper  fibres  end  in  the 
capsule  of  the  hip-joint  (Theile). 

This  muscle  is  covered  by  the  gluteus  medius  and  pyriformis,  and 
rests  on  the  hip-bone  and  joint.  At  the  anterior  border  is  placed  the 
tensor  of  the  fascia  lata;  and  at  the  hinder  edge,  the  lower  gemellus. 
On  it  lie  the  gluteal  vessels,  and  the  superior  gluteal  nerve. 

In  its  action  the  muscle  resembles  the  gluteus  medius.  Por  if  the 
femur  hangs  loosely  it  will  be  abducted;  and  it  may  be  rotated  in  by  the 
anterior  transverse  fibres.  When  the  body  is  supported  on  both  legs  this 
gluteus  will  act  in  balancing  the  pelvis;  and  when  the  trunk  is  rotated  on 
one  limb  it  will  bring  the  face  to  the  same  side.  At  the  beginning  of  a 
step  in  walking  it  advances  the  hindmost  leg  with  the  gluteus  medius,  and 
then  inclines  tlie  pelvis  over  the  supporting  femur  whilst  the  swinging 
limb  is  put  forwards. 

Obturator  internus  and  gemelli.  On  cutting  through  the  obturator, 
G,  and  raising  the  inner  end,  three  or  four  tendinous  j)ieces,  separated 
by  fleshy  intervals,  will  appear  on  the  under  surface;  and  the  subjacent 
bone  will  be  seen  to  be  provided  with  ridges  of  fibro-cartilage,  which 
correspond  with  the  fleshy  interspaces.  A  synovial  membrane  lubricates 
the  surfaces. 

Near  the  pelvis  the  gemelli  muscles,  F  and  H,  approach  each  other 
beneath  the  obturator,  but  near  the  femur  they  cover  the  tendon  of  the 
obturator;  and  all  three  of  them  pass  beneath  the  pyriformis  to  be 
inserted  in  front  of  it  into  the  trochanter  and  the  neck  of  the  femur.  In 
the  Drawing  the  muscles  are  separated  from  each  other  to  show  the  nerve 
to  the  quadratus,  8,  and  its  accompanying  artery. 

The  obturator  externus,  J,  arises  from  the  outer  surface  (in  part)  of 
the  obturator  membrane,  and  from  the  bone  bounding  anteriorly  the 
thyroid  hole.  From  this  widened  attachment  the  fibres  are  directed 
almost  horizontally  backwards  to  a  tendon,  which  is  inserted  into  the  pit 
at  the  root  of  the  trochanter. 

At  the  fore  part  of  the  thigh  the  obturator  is  covered  by  the  adductors 
(Plate  xxxvii.);  and  in  the  second  view  of  the  buttock  it  is  concealed  by 


SACRO-SCIATIO    LIGAMENTS.  147 

the  quadratis  femoris,  I,  except  a  j^art  of  the  tendou  which  is  apparent 
between  the  upper  border  of  the  quadratus  and  the  inferior  gemellus 
(Plate  XLix.).  As  the  muscle  passes  from  the  front  to  the  back  of  the 
limb  its  spreads  over  and  supports  the  lower  part  of  the  hip-joint.  Es- 
caping beneath  its  lower  border  is  the  internal  circumflex  artery. 

Like  the  other  rotators  out,  the  external  obturator  draws  backwards 
the  great  trochanter  when  the  femur  hangs  loosely;  and  even  when  the 
hiji-joint  is  flexed  it  Avill  execute  the  same  movement  of  the  thigh-bone, 
and  in  this  respect  it  differs  from  the  other  muscles  of  its  group.  "When 
the  limbs  are  fixed  as  in  standing  it  contributes  its  share  of  j)ower  in 
maintaining  the  pelvis  upright  on  the  femur;  and  in  standing  on  one  leg 
it  helps  also  to  fix  the  pelvis. 

Psoas  magnus,  K.  The  tendon  of  this  muscle  inclines  over  the 
hip-joint  and  the  neck  of  the  femur  to  its  insertion  into  the  small  tro- 
chanter. 

The  sacro-sciatic  ligaments  connect  the  back  of  the  hip-bone  to  the 
sacrum  and  coccyx:  they  are  two  in  number,  and  are  named  large  and 
small. 

The  large  ligament,  U,  is  wide  and  thin  internally,  but  thicker  and 
pointed  externally.  It  is  attached  by  its  widened  part  to  the  back  of  the 
hip-bone,  to  the  side  of  the  sacrum,  and  to  the  side  of  the  coccyx.  Its 
fibres  are  directed  backwards  and  outwards,  and  being  aggregated  to- 
gether, are  inserted  into  the  inner  side  of  the  ischial  tuberosity  and  lower 
border  of  the  hip-bone.  It  closes  below  the  great  sacro-sciatic  notch  of 
the  pelvis,  and  gives  origin  to  fibres  of  the  gluteus  maximus.  Branches 
of  the  gluteal  and  sciatic  arteries  perforate  the  ligament,  and  the  offsets 
of  the  posterior  sacral  nerves  lie  beneath  a  superficial  layer  of  its  fibres. 

The  small  ligament,  V,  unites  internally  with  the  larger  band,  and  is 
attached  with  it  to  the  side  of  the  sacrum  and  coccyx.  Its  constituent 
fibres  are  coarse,  and  pass  outwards  to  be  inserted  into  the  ischial  spine. 
By  its  position  it  divides  into  two  apertures  the  space  included  by  the 
hip-bone  and  the  great  ligament. 

The  upper  and  larger  aperture  or  notch  is  bounded  above  by  the  hip- 
bone, and  below  by  the  small  sacro-sciatic  ligament.  Through  it  are 
transmitted  the  pyriformis  muscle,  and  vessels  and  nerves.  Above  the 
muscle  issues  the  gluteal  artery,  a,  with  its  veins,  and  the  upper  gluteal 
nerve,  4;  and  below  the  muscle  issue  the  great  and  small  sciatic  nerves, 
6  and  12,  the  pudic  nerve,  10,  and  the  sciatic  and  pudic  vessels,  I  and  g. 


148 


ILLUSTRATIONS    OF    DISSECTIONS. 


The  lower  and  smaller  aperture  intervenes  between  the  attachments  of 
the  two  ligaments  to  the  hip-bone,  and  gives  passage  to  the  obturator 
internus  muscle,  G,  the  pudic  artery,  g,  with  its  veins,  the  pudic  nerve, 
10,  and  the  nerve  to  the  obturator  muscle,  9,  with  its  vessels. 


ARTERIES  OF  THE  BUTTOCK. 

Parts  of  the  gluteal,  sciatic,  and  pudic  arteries  of  the  internal  iliac; 
branches  of  the  internal  and  external  circumflex  arteries;  and  offsets  of 
the  first  perforating  artery  of  the  profunda,  are  included  in  the  dissec- 
tion* but  the  gluteal  and  internal  circumflex  will  be  referred  to  here 
more  esjoecially. 


a.  Trunk  of  gluteal. 

Z>.  Superficial  [  ^f  the  gluteal. 

c,  d.  Deep  branch     ' 
e.  Sciatic  artery,  cut. 
/.  Coccygeal  branches. 
g.  Pudic  artery. 
h.  Branch  of  the  quadratus. 
Z.   Ending  of  the  internal  circum- 
flex. 


n.  Transverse  j  of  the  circum- 

o.  Ascending  branch  )  flex. 

r.  First  perforating  of  the  profunda. 

s.  Branch  of  perforating  to  the  bi- 
ceps. 

t.  Ascending  branch  of  perforating 
to  join  circumflex. 

]\  Branches  to  the  sciatic  nerve  from 
the  sciatic  artery. 


The  gluteal  artery,  a,  escapes  from  the  pelvis  through  the  upper  part 
of  the  great  sacro-sciatic  notch,  as  before  said,  and  divides  into  superficial 
and  deep  muscular  branches. 

The  superficial  part,  I,  appears  between  the  gluteus  medius  and  the 
pyriformis  (Plate  xlix.),  and  pierces  the  under  surface  of  the  gluteus 
maximus  (p.  142). 

The  deep  part  divides  into  two  chief  branches,  which  are  continued 
forwards  between  the  gluteus  medius  and  minimus. 

One,  c,  courses  over  the  origin  of  the  gluteus  minimus  to  the  fore 
part  of  the  iliac  crest,  where  it  anastomoses  with  the  external  circum- 
flex of  the  profunda:  it  furnishes  branches  to  both  the  smaller  glutei, 
but  chiefly  to  the  medius;  and  some  offsets  ascend  over  tbe  iliac  crest  to 
communicate  with  arteries  in  the  wall  of  the  abdomen. 

The  other  branch,  d,  crosses  the  middle  of  the  smallest  gluteal  mus- 
cle, and  ends  in  front  by  supplying  the  tensor  of  the  fascia  lata,  and  by 
anastomosing,  like  the  upper  branch,  with  the  external  circumflex:  its 
offsets  are  given  to  the  two  muscles  between  which  it  lies,  but  most  belong 


ARTERIES  OF  THE  BUTTOCK.  149 

to  the  smallest  gluteus.  A  considerable  branch  jmsses  beneath  the  pyri- 
formis,  and  penetrates  the  fibres  of  the  gluteus  minimus;  some  of  its 
ramifications  are  prolonged  to  the  hip-joint. 

The  gluteal  veins  have  the  same  anatom^y  as  the  artery,  and  open  into 
the  internal  iliac  vein;  they  were  removed  in  the  dissection. 

The  sciatic  and  pud ic  arteries,  e  and  g,  have  been  described  with  the 
preceding  Plate  (p.  142).  Several  offsets  of  the  sciatic  artery,  which 
enter  the  great  sciatic  nerve,  are  marked  thus,  f . 

The  internal  circmnflex  artery  of  the  profunda,  I  (p.  133),  divides 
beneath  the  quadratus  into  two  terminal  branches, — ascending  and  trans- 
verse. 

The  ascending  branch,  o,  follows  the  obturator  externus  muscle  be- 
neath the  quadratus  femoris  to  the  pit  at  the  root  of  the  great  trochanter, 
and  anastomoses  there  with  the  gluteal  artery;  it  gives  small  muscular 
branches  to  the  quadratus,  obturator,  and  gemelli,  and  some  offsets  ex- 
tend to  the  surface  of  the  great  trochanter. 

The  transverse  branch,  n,  passes  back  between  the  borders  of  the 
quadratus,  I,  and  adductor  magnus,  L,  and  sends  branches  to  the  muscles 
attached  to  the  ischial  tuberosity,  some  small  offsets  reaching  the  surface 
of  both  the  adductor  and  the  great  sacro-sciatic  ligament,  as  in  the 
Figure.  It  anastomoses  beneath  the  hamstrings  with  the  highest  muscu- 
lar branch  of  the  profunda;  and  with  the  first  perforating  artery  of  the 
profunda,  r,  by  means  of  a  small  branch  which  crosses  the  upper  edge  of 
the  adductor  magnus  near  the  attachment  to  the  femur,  and  joins  the 
ascending  offset,  t,  from  that  perforating  artery. 

External  circumflex  of  the  profunda,  i.  The  ascending  branches  of 
this  artery  course  beneath  the  tensor  of  the  fascia  lata  to  the  hip-bone, 
where  they  supply  the  glutei  and  the  tensor,  and  anastomose  with  the 
gluteal  artery.  In  detaching  the  gluteus  medius  the  branches  to  it  were 
cut.     Offsets  from  it  are  given  to  the  trochanter. 

The  first  2Jerf orating  artery  of  the  profunda,  r  (p.  132),  comes  through 
the  adductor  magnus,  and  ends  in  the  vastus  externus;  it  supplies  offsets 
to  the  gluteus  maximus  and  the  long  head  of  the  biceps,  and  communi- 
cates by  the  branch,  t,  with  the  internal  circumflex. 


160  LLLU8TEATI0NS    OF    DI3SECTIOK8. 


NERVES  OF  THE  BUTTOCE:. 

Tlie  chief  nerres  of  the  buttock  appear  below  the  pyriformis,  and  are 
derived  from  the  sacral  plexus;  but  above  the  pyriformis  comes  the  upper 
gluteal  nerve;  and  on  the  great  sacro-sciatic  ligament  are  sacral  nerves. 


1,  2,  3.  Branches  of  the  posterior  sac- 
ral nerves. 
4,  5.  Branches     of     the    superior 
gluteal  nerve. 

6.  Branches  of  the  small  sciatic, 

cut. 

7.  Nerve  to  the  upper  gemellus. 


8.  Nerve  to  the  quadratus  femoris. 

9.  Nerve  to  the  obturator  intemus. 
10.  Pudic  nerve. 

12.  Great  sciatic  nerve. 
tf  Cutaneous  branches  of  the  sacral 
nerves. 


Posterior  sacral  nerves,  1,  2,  3.  These  are  the  external  branches  of 
the  posterior  primary  trunks  of  the  first  tlu'ce  sacral  nerves;  the  highest 
is  marked  with  number  1,  and  the  lowest  with  3.  At  first  they  are  di- 
rected out  beneath  the  multifidus  spinse  muscle,  and  then  unite,  in  the 
manner  shown  in  the  Figure,  beneath  a  thin  layer  of  fibres  of  the  great 
sacro-sciatic  ligament.  From  this  plexiform  union  of  the  nerves  two  or 
three  offsets  are  continued  through  the  gluteus  maximus  to  the  integu- 
ments of  the  buttock  (Plate  xlvii.).  The  nerves  are  not  always  joined 
in  the  manner  indicated. 

Ujjper  gluteal  nerve.  Springing  from  the  large  lumbo-sacral  trunk 
which  connects  together  the  lumbar  and  sacral  plexuses  (p.  70),  it  issues 
from  the  pelvis  above  the  pyriformis  muscle  with  the  gluteal  artery.  As 
soon  as  it  comes  into  sight  it  divides,  like  the  artery,  into  two  pieces, 
which  run  forwards  between  the  two  smaller  gluteal  muscles. 

The  upper  or  more  superficial  branch,  4,  enters  the  gluteus  medius; 
and  the  deeper  part,  5,  furnishes  offsets  to  both  the  gluteus  medius  and 
minimus,  and  ends  anteriorly  in  the  tensor  fasciae  latse. 

Bra/iiches  of  the  sacral  'plexus.  These  nerves  have  been  referred  to  in 
the  preceding  Plate,  but  some  of  them  are  more  fully  displayed  in  this 
deeper  dissection. 

The  tliigh-hranches  are  the  small  and  large  sciatic  nerves.  The 
branches  of  the  former  have  been  cut  across,  and  are  marked  with  6. 
The  larger  nerve  is  pointed  out  by  the  number  12. 


/    J 


% 


.^-^.-MfH 


.\^^  -.1 


PLATE  L! 


THE    POPLITEAL    SPACE.  151 

The  pudic  or  perincsal  nerve,  10,  is  directed  over  the  small  sacro-sciatic 
ligament  to  the  perinasum,  and  is  accompanied  by  the  pudic  artery  and 
the  nerve  to  the  obturator  interniis. 

Branches  to  external  rotators.  All  the  external  rotators,  except  the 
obturator  externus,  obtain  nerves  from  the  sacral  plexus.  The  obturator 
internus  receives  the  nerve,  9,  at  its  inner  or  pelvic  aspect.  To  the  upper 
gemellus  the  slender  nerve,  7,  is  distributed;  it  enters  the  superficial  sur- 
face. Two  nerves  enter  the  pyriformis  at  the  under  surface,  but  these 
are  not  visible  until  the  muscle  has  been  cut  and  reflected. 

The  quadratus  and  inferior  gemellus  are  supplied  by  the  nerve,  8, 
which  passes  beneath  the  upper  gemellus  and  the  obturator  internus,  and 
pierces  the  under  surface  of  the  quadratus  near  the  upper  border.  As 
the  nerve  crosses  under  the  inferior  gemellus  it  sends  an  offset  to  that 
muscle;  and  as  it  lies  on  the  capsule  of  the  hip-joint,  fine  filaments  pene- 
trate that  membrane  to  end  in  the  synovial  sac. 


DESCRIPTION  OF  PLATE  LI. 


The  popliteal  space  or  the  ham,  with  its  contents,  is  delineated  in  this 
Figure. 

For  the  dissection  of  the  ham  the  skin  and  the  deep  fascia  are  to  be 
reflected  by  a  median  incision,  terminated  by  a  cross  cut  at  each  end. 
The  large  quantity  of  fat,  which  then  comes  into  view,  is  to  be  removed 
with  care;  for  articular  vessels  and  nerves,  and  other  nerves  and  arteries 
to  muscles,  cross  through  the  deeper  region  of  the  hollow.  On  the  side 
of  the  artery  some  lymphatic  glands  are  to  be  separated  from  the  sur- 
rounding fat. 


FORM,  SIZE,   AND  BOUNDARIES. 

The  ham  is  placed  at  the  back  of  the  knee-joint,  and  corresponds  with 
the  interval  in  front  of  the  elbow  in  the  upper  limb.  Like  the  intermus- 
cular space  which  it  resembles,  it  is  situate  on  that  aspect  of  the  joint  to 


152  ILLUSTEATIONS    OF    DISSECTIONS. 

which  flexion  takes  place,  and  lodges  the  main  vessels  and  nerves  of  the 
limb. 


A.  Biceps  cruris. 

B.  Semimembranosus. 

C.  Semitendinosus. 

D.  Gracilis. 


E.  Sartorius. 

F.  Plantaris. 

G.  Outer  head      )    of  the  gastro- 


H.  Inner  head      \        cnemius 


In  form  the  popliteal  space  is  lozenge-shaped,  with  the  points  directed 
up  and  down.  Before  its  lateral  boundaries  are  disturbed  it  extends  about 
two  inches  and  a  half  above  the  knee-joint,  and  downwards  about  one 
inch  and  a  half  from  the  same  point;  but  its  length  will  vary  with  the  de- 
gree of  separation  of  the  hamstring  muscles. 

This  hollow  is  produced  by  the  arrangement  of  the  muscles  at  the 
knee,  for  the  hamstrings  and  the  heads  of  the  gastrocnemius  and  the 
jilantaris,  as  they  pass  the  joint,  are  collected  on  the  sides  of  the  limb, 
and  give  rise  thus  to  the  angular  interval  of  the  popliteal  space.  By  the 
removal  of  the  muscles  from  the  midline  of  the  limb  to  the  side,  greater 
extent  of  bending  is  permitted  in  the  joint. 

Towards  the  surface  the  ham  is  closed  by  the  teguments,  and  by  the 
fascia  lata  strengthened  by  transverse  fibres  from  the  tendons  of  the  ham- 
strings. And  the  bottom  of  the  space  is  formed  by  the  femur  and  the 
knee-joint. 

Laterally  it  is  inclosed  by  the  intermuscular  septa,  which  are  inserted 
into  the  condyloid  lines  of  the  femur,  and  by  the  following  muscles.  On 
the  outer  side  lies  the  biceps  muscle.  A,  as  low  as  the  condyle  of  the  fe- 
mur; and  below  that  point  come  the  plantaris,  F,  and  outer  head  of  the 
gastrocnemius,  G.  On  the  inner  side  it  is  limited  as  low  as  the  condyle 
by  the  semimembranosus,  B;  by  the  semitendinosus,  C,  lying  on  the 
other;  and  by  the  sartorius  and  gracilis,  D  and  E,  which  intervene  be- 
tween the  semimembranosus  and  the  femur;  and  below  the  condyle  is 
situate  the  inner  head  of  the  gastrocnemius,  H. 

The  upper  and  lower  points  or  angles  are  constructed  also  by  mus- 
cles. At  the  upper,  the  biceps.  A,  and  semitendinosus,  C,  are  in  con- 
tact ;  and  at  the  lower,  the  inner  head  of  the  gastrocnemius,  H,  comes 
into  apposition  with  the  plantaris  and  the  outer  head  of  the  gastrocne- 
mius, F  and  G. 

The  depth  of  the  space  is  greater  above  than  below  the  knee-joint, 


'  VESSELS    OF   THE   HAM. 


153 


and  is  greatest  opposite  the  iuter-condyloid  hollow  of  the  femur.  The 
widest  part  is  on  a  level  with  the  condyles  of  the  femur. 

The  ham  is  closed  on  all  sides  except  above  and  below,  and  at  those 
spots  it  communicates  with  the  back  of  the  thigh  and  leg.  .  Above,  a 
probe  can  be  pushed  under  the  hamstrings  along  the  course  of  the 
internal  2:)opliteal  nerve  ;  and  below,  it  can  be  passed  under  the  gastro- 
cnemius, by  the  side  of  the  great  bloodvessels.  Blood  poured  out  from 
the  vessels  into  the  hollow  would  diffuse  itself  under  the  muscles  of  the 
thigh  and  leg  in  the  channels  indicated. 

In  the  popliteal  space  are  contained  the  large  bloodvessels  and  nerves 
of  the  limb,  with  their  branches ;  a  branch  of  the  obturator  nerve  ;  an 
offset  of  the  small  sciatic  nerve,  with  its  artery,  and  lymphatics,  with 
much  fat. 


VESSELS   OF    THE   HAM. 

The  chief  vessels  in  the  ham  are  the  popliteal  artery  and  vein,  which 
wind  from  the  fore  part  to  the  back  of  the  limb  above  the  knee,  so  as  to 
pass  the  knee-joint  on  the  flexion-side  i  but  branches  of  those  trunks 
cross  th.e  space,  and  a  small  superficial  artery,  accompanying  the  small 
sciatic  nerve,  is  continued  through  it  to  the  leg. 


a.  Popliteal  artery. 

1).  Upper  external  articular. 

c.  Upper  internal  articular. 

d.  Cutaneous  branches  with  veins. 

e.  Cutaneous  branch  with  the  small 

sciatic. 
/.  Cutaneous  branch  of  the  anasto- 
motic. 


g.  Internal  sural  to  gastrocnemius. 

h.  Short  saphenous  vein. 

i.   Cutaneous  veins  of  the  back  of  the 

leg. 
I.    Popliteal  vein. 
n.  External  sural  artery  to  the  gas- 

trocnemiuns. 


The  popliteal  artery,  a,  begins  and  ends  beyond  the  limits  of  the 
space  now  defined.  The  part  of  the  artery  contained  in  the  ham  courses 
obliquely  from  the  inner  side  above  to  the  mid-point  of  the  space  below. 
At  first  it  issues  from  beneath  the  semimembranosus,  B,  but  it  lies  after- 
wards in  the  hollow  between  the  condyles  of  the  femur  and  the  heads  of 
the  gastrocnemius.  It  is  deeply  placed  throughout,  and  rests  on  the 
lower  end  of  the  femur  and  the  knee-joint.  Internally  it  is  in  contact 
with  the  semimembranosus,  B,  and  with  the  inner  head  of  the  gastro- 


154:  ILLU8TBATION8    OF    DISSECTIONS. 

cnemius,  H  ;  and  the  first  muscle  would,  serve  as  a  guide  to  the  posi- 
tion of  the  vessel.  It  has  the  following  connections  with  veins  and 
nerves: 

The  popliteal  vein,  I,  is  closely  united  to  the  artery  throughout.  At 
the  upper  end  of  the  space  ib  is  external  to  the  arterial  trunk,  whilst 
towards  the  lower  end,  or  between  the  heads  of  the  gastrocnemius,  it 
becomes  superficial  to  that  vessel.  Some  small  cutaneous  veins,  i,  cross 
the  inner  side  of  the  artery  in  their  course  to  join  the  poi^liteal  vein. 

The  internal  popliteal  nerve,  3,  passes  through  the  ham  from  the 
upper  to  the  lower  angle,  and  is  much  more  superficial  than  the  blood- 
vessels. At  first  it  lies  outside  the  line  of  the  vascular  trunks,  but 
is  placed  over  these  between  the  heads  of  the  ga-strocnemius.  Some  of 
its  branches  touch  the  vessels  ;  for  instance,  the  short  saphenous  nerve, 
4,  lies  on  the  popliteal  trunks  below,  and  the  nerve,  6,  to  the  inner  head 
of  the  gastrocnemius,  crosses  them  ;  further,  the  azygos  articular  nerve, 
7,  enters  the  back  of  the  joint  beneath  the  vessels. 

Much  more  superficial  than  the  internal  popliteal  trunk,  3,  is  the 
continuation  of  the  small  sciatic  nerve,  2,  with  accompanying  vessels  ; 
and  resting  on  the  popliteal  artery  is  the  articular  branch  of  the  obtura- 
tor nerve. 

Branches  of  the  artery.  In  the  popliteal  space  the  artery  furnishes 
muscular  and  articular  branches. 

Muscular  "branches.  These  are  supplied  from  the  upper  and  lower 
parts  of  the  trunk.  The  upper  enter  the  biceps  and  semimembranosus  ; 
and  the  lower  or  sural,  g  and  n,  are  distributed  to  the  heads  of  the  gas- 
trocnemius and  the  plantaris. 

Articular  arteries.  Only  the  upper  pair  is  visible;  and  the  two  are 
attached  to  the  arterial  trunk  rather  above  the  knee-joint.  The  outer 
branch,  h,  crosses  the  femur  above  the  condyle,  and  passing  under  the 
biceps,  leaves  the  ham  by  perforating  the  external  intermuscular  septum. 
The  inner,  a,  is  directed  beneath  the  inner  hamstrings  and  the  tendon  of 
the  adductor  magnus  to  the  front  of  the  knee-joint, 

A  single  median  (azygos)  articular  branch  enters  the  joint  through 
the  posterior  ligament,  but  it  is  concealed  by  the  trunks  of  the  vessels. 


NERVES    OF    THE    POPLITEAL    SPACE. 


155 


NERVES  OF  THE  SPACE. 

In  the  ham  are  lodged  the  two  great  trunks  into  which  the  sciatic 
nerve  splits,  with  branches  of  these;  and  in  the  space  are  offsets  of  the 
small  sciatic  and  obturator  nerves. 


1.  Internal  cutaneous  of  the  thigh. 

2.  Small  sciatic  nerve. 

3.  Internal  popliteal  nerve. 

4.  Short  saphenous  nerve. 

5.  6.  Branches  to  the  heads  of  the 

gastrocnemius. 


7.  Middle  articular  branch 

8.  External  articular  branch. 

9.  Communicating  peroneal  branch. 

10.  External  cutaneous  of  the  leg. 

11.  External  popliteal  nerve. 


Popliteal  nerves.  At  the  back  of  the  thigh  the  sciatic  nerve  divides 
into  the  internal  and  external  popliteal  trunks  (Plate  lii.);  these  are  con- 
tinued through  the  ham  to  the  leg,  and  furnish  branches  to  the  surround- 
ing parts. 

The  internal  or  larger  trunk,  3,  lies  nearly  in  the  middle  of  the  limb, 
and  takes  the  position,  before  said,  to  the  bloodvessels  (p.  154) :  it  gives 
articular  branches  to  the  knee-joint;  muscular  to  the  gastrocnemius,  plau- 
taris,  and  soleus;  and  a  cutaneous  nerve  (short  saphenous)  to  the  back 
and  outer  part  of  the  leg. 

The  external  popliteal,  11,  is  placed  under  cover  of  the  biceps  muscle, 
and  leaves  the  space  below  to  reach  the  fore  part  of  the  leg.  Near  its 
commencement  it  gives  an  articular  nerve,  8,  to  the  knee-joint;  and 
whilst  it  is  contained  in  the  space  two  or  three  cutaneous  nerves  to  the 
back  and  outer  part  of  the  leg  arise  from  it.  No  muscles  receive  branches 
from  this  trunk. 

The  small  sciatic  nerve,  2,  is  continued  through  the  popliteal  space, 
immediately  beneath  the  fascia  lata,  to  end  in  the  integuments  of  the 
back  of  the  leg  (Plate  Liii.). 

The  obturator  nerve  courses  along  the  jDopliteal  artery  to  reach  the 
knee-joint,  to  which  it  is  distributed:  it  is  more  fully  seen  in  the  follow- 
ing Plate. 

Lymphatics.  Large  lymphatic  vessels  with  some  glands  lie  along  the 
bloodvessels.     The  glands  are  three  or  four  in  number,  and   through 


156 


ILLDSTEATIONS    OF    DISSECTIONS. 


them  pass  tiie  lymphatics  accompanying  the  tibial  bloodvessels  and  the 
short  saphenous  yein. 

Fat  in  tlie  liam.  A  loose  granular  fat,  similar  to  that  in  the  ischio- 
rectal fossa^  fills  the  popliteal  space,  and  surrounds  loosely  the  vessels  and 
nerves,  so  as  to  permit  their  necessary  displacement  in  the  m^ovements  of 
the  knee-joint.  Above  and  below  it  is  continuous  with  the  areolar  tissue 
and  fat  of  the  thigh  and  leg.  Abscesses  form  readily  in  it,  and  may 
acquire  large  size  without  giving  rise  either  to  swelling  on  the  surface, 
or  to  fluctuation.  From  the  strength  and  completeness  of  the  subcuta- 
neous boundary  the  pus  does  not  find  its  way  readily  to  the  surface;  and 
to  prevent  this  fluid  burrowing  upwards  and  downwards  under  the 
muscles,  where  the  popliteal  space  is  not  closed  by  fascia,  incisions  should 
be  made  through  the  fascia  lata. 


DESCRIPTION  OF  PLATE  LII. 


I2f  this  Figure  a  view  of  the  dissection  of  the  back  of  the  thigh  is 
given. 

After  the  popliteal  space  has  been  examined,  the  hinder  part  of  the 
thigh  may  be  exposed,  by  slitting  up  and  reflecting  the  skin  and  the 
fascia  between  the  ham  and  the  buttock.  The  surface  of  the  muscles 
having  been  cleaned,  these  maybe  separated  from  each  other  to  trace  the 
vessels  and  nerves. 

MUSCLES  OF  THE  BACK  OF  THE  THIGH. 

Behind  the  femur  are  situate  the  flexor  muscles  of  the  hip-joint, 
which  are  called  commonly  the  hamstrings.  At  this  stage  of  the  dissec- 
tion the  insertion  of  the  gluteus  maximus  can  be  better  seen  than  in 
Plate  XLViii.,  Avhere  the  muscle  is  delineated. 


A.B.C. 

D. 

E.  F. 

G. 
H. 


Insertion    of     the    gluteus 

maximus. 
Quadratus  femoris. 
Insertion  of  the    adductor 

magnus. 
Long  head  of  the  biceps. 
Short  head  of  the  biceps. 


I.  Ischial  part  of  the  adductor  mag- 
nus. 

J.  Semitendinosus. 

K.  Semimembranosus. 

L.  Outer  head  of  the  gastrocnemius. 

N.  Inner  head  of  the  gastrocne- 
mius. 


PLATE  Li! 


HAMSTRING    MUSCLES.  157 

Insertion  of  ilie  gluteus  maximus.  The  fibres  of  this  muscle  are 
inserted  partly  into  the  fascia  lata,  and  partly  into  the  femur.  About 
the  upper  two-thirds  of  the  whole  (as  far  as  A)  end  in  the  fascia  lata. 
The  remaining  fibres  are  inserted  by  two  parts; — one,  B,  the  larger, 
is  fixed  into  the  line  leading  from  the  linea  aspera  to  the  great  trochanter; 
and  the  other,  C,  ends  in  the  fascia  lata. 

Biceps  flexor  cruris.  The  muscle  consists  of  two  heads,  long  and 
short. 

The  long  head,  G,  is  spindle-shaped,  and  arises  from  the  lower  part 
of  the  ischial  tuberosity  in  common  with  the  semitendinosus.  The  short 
head,  H,  which  is  flattened,  takes  origin  from  the  linea  aspera,  and  from 
nearly  the  whole  of  the  outer  condyloid  line  of  the  femur,  as  well  as 
from  the  external  intermuscular  septum.  Both  heads  blend  below  in  a 
tendon,  which  is  divided  into  two  pieces  by  the  external  lateral  ligament 
of  the  knee-joint,  and  is  inserted  mainly  into  the  head  of  the  fibula,  but 
a  small  part  is  prolonged  to  the  head  of  the  tibia:  from  the  tendon  a  pro- 
cess is  continued  to  the  fascia  of  the  leg. 

Uncovered  by  muscle  excej)t  above,  where  the  gluteus  maximus  con- 
ceals it,  the  biceps  lies  on  the  adductor  magnus,  and  crosses  the  great 
sciatic  nerve.  To  its  inner  side  is  the  semitendinosus,  J.  In  the  lower 
fourth  of  the  thigh  it  bounds  externally  the  hollow  of  the  ham,  and  forms 
the  outer  hamstring.  Between  the  external  lateral  ligament  of  the  knee- 
joint  and  the  tendon  of  insertion  a  synovial  bursa  intervenes. 

When  the  tibia  is  free  to  move  the  muscle  combines  with  the  other  ham- 
strings in  drawing  backwards  that  bone  and  flexing  the  knee;  and  after 
the  joint  has  been  bent  it  will  rotate  outwards  the  foot.  If  the  bones 
of  the  leg  are  fixed,  it  will  assist  its  fellow  in  propping  the  pelvis  on  the 
femur;  and  if  the  lower  limb  is  movable  at  the  hip,  but  immovable  at 
the  knee-joint,  the  muscle  Avill  bring  down  and  back  the  raised  femur, 
thus  checking  flexion  of  the  hip,  and  will  help  in  jDutting  back  the  leg 
in  the  process  of  walking  backwards. 

The  sejnitendinosus,  J,  is  named  from  its  long  tapering  tendon  near 
the  knee.  It  arises  from  the  ischial  tuberosity  and  the  tendon  of  the 
biceps.  Its  fibres  form  at  first  a  flat  muscle;  but  this  becomes  round 
telow,  and  ends  at  the  lower  third  of  the  thigh  in  a  tendon,  which  is 
inserted  into  the  inner  side  of  the  tibia  close  below  the  gracilis  (Plate 

XLYII.). 

Like  the  other  hamstrings,  it  is  covered  above  by  the  gluteus  maxi- 


158  ILLUSTRATIONS    OF    DISSECTIONS. 

mus,  and  it  rests  on  the  semimembranosus.  To  its  outer  side  is  the 
biceps  as  far  as  the  popliteal  space.  At  the  insertion  a  synovial  mem- 
brane envelops  the  tendon;  and  under  the  muscle  at  its  origin  is  placed 
another  bursa  (Theile).  A  tendinous  line  crosses  the  muscle  obliquely 
from  the  inner  to  the  outer  side,  so  as  to  divide  it  into  an  upper  and 
lower  part,  but  some  of  the  under  fibres  pass  over  this  intersecting  band. 

Acting  from  the  pelvis  the  muscle  bends  the  knee-joint;  and  it  will 
afterwards  rotate  in  the  foot.  The  leg  being  fixed  and  the  hip-joint 
free  to  move,  the  muscle  balances  the  pelvis.  It  will  put  back  the  raised 
femur  in  the  same  way  as  the  biceps. 

The  semimembranosus,  K,  is  the  largest  of  the  hamstrings,  and  arises 
by  a  tendon  from  the  ischial  tuberosity,  external  to  and  rather  above 
the  other  two  muscles.  From  this  tendon  which  widens  and  becomes 
thin  at  the  inner  edge,  but  is  thickened  and  rounded  at  the  outer,  the 
fleshy  fibres  spring,  and  form  below  a  rounded  belly.  Infenorly  the 
muscle  is  terminated  by  a  second  tendon,  which  is  inserted  into  a  groove 
on  the  inner  tuberosity  of  the  head  of  the  tibia,  and  sends  off  the  three 
following  fibrous  processes: — one  backwards  to  join  the  capsule  of  the 
knee-joint;  another  forwards  to  blend  with  the  internal  lateral  ligament 
of  that  joint;  and  a  third  downwards  to  unite  with  the  fascia  covering 
the  j3opliteus  muscle.  At  the  insertion  a  small  bursa  is  interposed 
between  the  tendon  and  the  bone. 

Crossing  beneath  the  other  hamstrings  it  is  hollowed  out  above  to  lodge 
the  semitendinosus.  Beneath  it  is  the  abductor  magnus.  In  the  lower 
third  of  the  thigh  it  bounds  internally  the  ham,  and  jorojects  into  that 
hollow  so  as  to  cover  the  popliteal  vessels.  Between  its  lower  tendon  and 
the  inner  head  of  the  gastrocnemius  is  a  bursa,  which  is  oftentimes  en- 
larged and  contains  a  thick  glairy  reddish  fluid. 

Being  stronger  than  the  semitendinosus  it  acts  more  powerfully  in 
bending  the  knee-joint,  and  in  rotating  inwards  the  foot,  supposing  the 
tibia  to  be  the  part  moved.  In  the  standing  posture  the  pelvis  is  propped 
by  it  and  the  other  hamstrings.  In  attempts  to  flex  the  hip-joint,  whilst 
the  knee  is  kept  extended,  it  can  be  used  to  check  the  elevation  of  the  fe- 
mur. In  concert  with  its  fellows  it  will  depress  and  move  back  the  femur, 
as  in  walking  backwards.  After  the  body  has  been  bent  forwards,  as  in 
stooping,  the  muscle  will  draw  down  and  back  the  ischial  tuberosity,  and 
place  the  pelvis  in  the  erect  position. 

Adductor  magmis.     This  large  fleshy  muscle  separates  the  liamstrings, 


VESSELS    OF    THE    BACK    OF    THE    THIGH. 


159 


and  the  nerves  and  vessels  at  the  back  of  the  tliigh,  from  tlie  femoral 
vessels  and  the  other  adductor  muscles.  Near  the  attachment  to  the 
lower  end  of  the  linea  aspera  the  femoral  vessels  pass  from  before  back 
through  an  aperture  in  it,  which  is  fleshy  behind  but  tendinous  in  front: 
this  hole  is  bounded  externally  by  the  slip,  F,  which  is  fixed  for  a  short 
distance  to  the  inner  condyloid  line;  and  internally  by  the  strong  fibres, 
I,  coming  from  the  ischial  tuberosity,  and  ending  in  a  tendon  which  is 
fixed  to  the  inner  condyle  of  the  femur. 


VESSELS  OF   THE   BACK  OF  THE  THIGH. 

Many  branches  of  the  profunda  artery  pierce  the  adductor  magnus, 
and  ramify  in  the  hamstrings.  Below  that  muscle  lie  the  popliteal  ves- 
sels and  their  branches.  And  in  the  region  of  the  buttock  some  small 
branches  of  the  sciatic,  pudic,  and  internal  circumflex  arteries  are  delin- 
eated. 


Arteries. 

a.  Inferior  haemorrhoidal  of  the  pu- 

dic. 

b.  Small  sciatic. 

c.  Internal  circumflex. 

d.  First  perforating  branch. 

e.  Second  perforating. 
/.  Third  perforating. 

g.  Muscular  branches  of  profunda. 


i.   Popliteal  artery. 

j.  Muscular  branch  of  popliteal. 

k.  Upper  external  articular  branch. 

I.   Upper  internal  articular. 

n.  Inner  sural  branch. 

r.  Outer  sural  branch. 

Veins. 
o.  Popliteal  vein. 
p.  Short  saphenous. 


Branches  of  the  internal  iliac.  The  two  branches  here  seen  have 
been  previously  referred  to  with  the  description  of  other  Plates: — a,  marks 
the  inferior  licBmorrlioidal  branch  of  the  pudic,  which  supplies  the  sphinc- 
ter ani  and  the  gut  (Plate  xxix.);  and,  l,  points  out  the  ramifications  of 
the  small  sciatic  artery  at  the  lower  border  of  the  gluteus  maximus  (Plate 

XLIX.). 

Brandies  of  the  profunda.  Most  of  the  branches  of  the  profunda, 
viz.,  perforating  and  muscular,  are  directed  to  the  back  of  the  thigh 
through  the  adductor  magnus,  and  ramify  in  the  hamstrings :  one  (inter- 
nal .circumflex)  runs  above  the  adductor. 

Internal  circumflex,  c.  The  transverse  branch  of  this  artery  passes 
between  the  edges  of  the  quadratus  femoris,  D,  and  adductor  magnus,  I, 
and  supplies  the  hamstring  muscles  (p.  149). 


160  ILLUSTRATIONS    OF    DISSECTIONS. 

The  perforating  artej'ies  are  four  in  number,  and  are  derived  from 
the  profunda  on  the  front  of  the  thigh  (p.  132).  All  of  them  pierce  the 
adductor  magnus  near  its  attachment  to  the  femur, — the  first  appearing 
near  the  top  of  the  muscle,  and  the  last  near  the  lower  end  of  the  linea  as- 
pera;  and  all,  except  the  first,  are  more  or  less  concealed  by  the  biceps. 
The  first  is  marked  with  d,  the  second  with  e,  and  the  cutaneous  part  of 
the  third  with/;  they  haye  the  following  distribution: — 

They  (excej)t  the  first)  are  directed  outwards  close  to  the  linea  aspera, 
and  through  the  short  head  of  the  biceps  and  the  external  intermuscular 
septum  to  the  vastus  externus  and  internus  muscles,  in  which  they  are 
■distributed,  maintaining  communications  with  their  fellows  and  with  the 
•descending  branches  of  the  external  circumflex  artery.  In  the  first  artery, 
d,  of  the  set  there  is  a  difference  in  its  course,  for  it  is  higher  than  the 
short  head  of  the  biceps,  and  pierces  the  gluteus  maximus.  In  its  pas- 
sage each  furnishes  a  branch  to  the  long  head  of  the  biceps,  except  the 
fourth  when  it  :s  small;  and  as  each  artery  pierces  the  short  head  of  the 
biceps  it  gives  a  small  offset  to  that  muscle. 

A  cutaneous  Irancli  is  given  off  from  each  of  the  three  first;  and  this 
enters  the  fat  along  the  line  of  the  outer  intermuscular  septum. 

Muscular  or  anadomotic  Iranclies  of  the  profunda.  These  are  dis- 
tinct from  the  perforating  arteries  (p.  132),  and  pierce  the  adductor 
.magnus  internal  to  those  vessels.  Generally  four  in  number,  most  of 
them  are  concealed  by  the  inner  hamstrings,  but  the  two  which  are  visi- 
ble in  the  Figure  are  marked  with  g. 

The  highest  is  placed  outside  the  line  of  the  others  and  appears  about 
five  inches  from  the  ischial  tuberosity:  it  supplies  the  semitendinosus 
.and  biceps,  and  anastomoses  with  the  internal  circumflex.  The  remain- 
ing three  come  out  in  a  line  through  a  cleft  between  the  fibres  of  the 
:adductor,  and  about  two  inches  from  each  other:  they  end  mostly  m  the 
semimembranosus,  but  one  or  more  may  give  offsets  also  to  the  biceps  and 
semitendinosus,  as  is, the  case  with  the  lowest  in  this  Plate.  Offsets  are 
furnished  from  them  to  the  great  sciatic  nerve. 

These  vessels  serve  the  purpose  of  maintaining  at  the  back  of  the 
thigh  communications  with  each  other  in  the  hamstring  muscles,  and 
with  branches  of  the  popliteal  artery. 

Near  the  inner  border  of  the  adductor  magnus  some  small  cutaneous 
branches  issue  from  the  muscular  fibres  to  end  in  the  integuments. 

The  popliteal  artery,  i,  continues  the  femoral  trunk  from  the  front 


POPLITEAL    ARTERY.  161 

of  the  tliigli  to  the  back  of  the  knee,  and  is  represented  in  the  upper 
limb  by  the  lower  part  of  the  brachial  artery.  Named  from  its  j3osi- 
tion  in  the  popliteal  space,  it  extends  from  the  opening  in  the  adductor 
magnus  to  the  lower  border  of  the  popliteus  muscle,  where  it  divides 
into  two — anterior  and  posterior  tibial  arteries.  As  its  connections  in 
the  lower  part  of  the  thigh  differ  greatly  from  those  in  the  leg,  it  may 
be  divided  into  two  parts  for  the  purposes  of  description. 

The  upper  and  longer  part,  i,  reaches  to  the  knee-joint,  and  is  con- 
tained in  the  popliteal  space.  It  is  placed  deeply  in  the  upper  part  of 
the  ham,  but  it  becomes  more  superficial  below  in  consequence  of  the 
projection  backwards  of  the  femur,  and  the  decreasing  thickness  of  the 
limb.  Its  direction  is  oblique  from  the  inner  side  of  the  femur  to  the 
middle  of  the  joint.  At  first  it  is  overlapped  by  the  semimembranosus, 
K,  as  far  as  the  condyles  of  the  femur,  but  thence  to  the  joint  it  is  cov- 
ered by  the  teguments,  the  fascia  lata,  the  fat,  and  by  veins  and  nerves. 
Beneath  the  vessel,  from  above  down,  are  placed  the  lower  end  of  the 
femur,  and  the  posterior  ligament  of  the  knee-joint.  Above  the  condy- 
les of  the  femur  the  artery  is  nearer  the  inner  than  the  outer  side  of  the 
space;  and  beyond  that  point  it  lies  between,  and  close  to  the  heads  of  the 
gastrocnemius,  L  and  N,  with  the  plantaris. 

The  popliteal  vein,  o,  is  closely  united  to  the  artery  throughout,  but 
it  changes  its  j)osition  in  the  following  way: — as  far  as  the  condyles  of 
the  femur  the  vein  is  superficial  and  external,  so  as  to  leave  only  a  nar- 
row arterial  strip  visible  internally,  but  onwards  to  the  joint  the  vein 
covers  the  artery.  Over  the  artery  between  the  heads  of  the  gastroc- 
nemius lies  the  short  saphenous  vein,  with  cutaneous  and  muscular 
branches  of  arteries,  veins,  and  nerves. 

Two  nerves  accompany  the  arteiy,  viz.,  the  internal  popliteal  and  the 
obturator.  The  popliteal  trunk  passes  vertically  along  the  middle  of 
the  limb,  from  the  upper  to  the  lower  point  of  the  ham,  and  lies  exter- 
nal to,  and  much  more  superficial  than  the  bloodvessels;  but  between  the 
condyles  of  the  femur  it  is  brought  much  nearer  to  the  vessels,  and  lower 
down,  between  the  heads  of  the  gastrocnemius,  it  is  placed  over  the 
artery  and  vein.  Some  of  the  branches  of  this  large  trunk  come  into 
contact  with  the  artery: — thus  the  posterior  articular  nerve  to  the  joint, 
2,  crosses  under  the  artery;  and  the  short  saphenous  nerve,  4,  lies  over 
the  bloodvessel  in  the  interval  between  the  heads  of  the  gastrocnemius. 
11 


162  ILLUSTRATIONS    OF    DISSECTIONS. 

The  obturator  nerve,  1,  runs  on  the  artery  as  far  as  the  knee-joint,  in 
which  it  ends. 

From  this  part  of  the  arterial  trunk  muscular  and  articular  arteries 
are  supplied,  the  former  coming  off  near  the  top  of  the  ham,  and  the 
latter  near  the  knee-joint.  All  are  so  small  in  size  as  not  to  disturb  the 
reparative  process  which  would  be  set  up  in  the  parent  trunk  after  a  liga- 
ture has  been  applied  to  it. 

Peculiarities.  Very  few  variations  in  the  course  and  condition  of  the 
artery,  and  in  the  surrounding  parts  are  met  with.  Perhaps  the  most 
noteworthy  change  in  the  artery  is  its  bifurcation  into  the  two  tibials  op- 
posite the  knee-joint,  instead  of  below  that  articulation. 

The  position  of  the  companion  vein  to  the  artery  is  inconstant,  at  one 
time  covering  more  of  that  bloodvessel  than  at  another;  and  not  very  un- 
frequently  the  vein  and  artery  change  places. 

Ligature.  Should  circumstances  render  ligature  of  the  popliteal  ar- 
tery necessary,  the  spot  best  suited  for  its  application  would  be  about  an 
inch  above  the  condyles  of  the  femur,  where  there  are  only  small  collateral 
branches,  and  where  the  connections  are  not  complicated.  The  surface 
guide  for  the  first  incision  will  be  the  line  of  direction  of  the  artery,  and 
the  vessels  will  be  arrived  at  by  cutting  vertically  down  through  the  fat 
towards  the  femur.  The  depth  of  the  vessel  may  be  diminished  during 
an  operation  by  bending  the  knee  so  a^  to  relax  the  sides  of  the  ham. 
On  attempting  to  separate  the  vein  from  the  artery  it  should  be  remem- 
bered that  the  two  are  very  closely  united  together,  and  that  sometimes 
the  artery  is  external  to  the  vein. 

Compression.  Whilst  the  popliteal  artery  is  contained  in  the  inter- 
muscular space  behind  the  knee,  pressure  can  be  applied  to  impede  the 
current  of  the  circulating  fluid.  Bending  the  knee  too,  so  as  to  make 
the  calf  of  the  leg  touch  the  back  of  the  thigh,  will  compress  to  a  certain 
extent  the  artery,  and  will  control  the  circulation  of  the  blood  in  it;  and 
this  kind  of  pressure  has  been  employed  with  success  in  later  times  in  the 
treatment  of  aneurism  of  the  popliteal  artery. 

Branches  of  this  part  of  the  artery.  These  consist  of  muscular  and 
articular,  as  before  said. 

Upper  muscular  branches.  Three  or  four  in  number  they  spring  from 
the  popliteal  trunk  soon  after  it  enters  the  ham:  they  supply  the  semi- 
membranosus and  biceps,  but  most  enter  the  former  muscle;  and  in  those 


NERVES    OF   THE    BACK    OF    THE    THIGH. 


163 


muscles  thoy  cominuuiciite  with  the  perforating  and  muscular  Ijranche.s 
of  the  profunda. 

The  articular  arteries  ramify  over,  and  in  the  knee-joint.  They  are 
five  in  number,  viz.  an  upper  and  a  lower  pair,  with  a  single  central 
branch,  but  only  the  upper  pair  comes  into  this  dissection. 

The  upper  pair  of  articular  branches  leave  the  sides  of  the  jiarent 
trunk,  and  are  directed  over  the  femur  to  the  front  of  the  limb.  The 
external,  h,  passes  beneath  the  biceps,  and  the  internal,  I,  beneath  the 
adductor  magnus  and  the  other  muscles  bounding  internally  the  ham;  on 
the  fore  part  of  the  knee  they  end  in  muscular  branches  to  the  triceps, 
and  in  anastomotic  branches  over  the  joint. 

The  middle  or  azygos  artery  penetrates  into  the  joint  through  the 
posterior  ligament;  it  is  concealed  by  the  large  popliteal  nerve. 

The  popliteal  vein,  o,  has  the  same  extent,  and  the  same  connections 
with  surrounding  parts  as  the  artery,  but  its  position  to  that  vessel 
changes.  Between  the  heads  of  the  gastrocnemius  it  conceals  entirely 
the  artery,  but  higher  up  the  artery  becomes  more  and  more  uncovered, 
and  at  the  opening  in  the  adductor  magnus  the  vein  is  quite  external. 

Its  contributing  branches  are  muscular  and  articular,  corresponding 
with  those  of  the  artery,  and  it  receives  in  addition  the  short  saphenous 
vein,  j»,  opposite  the  "back  of  the  joint. 


NERVES  OF  THE  BACK  OF  THE  THIGH. 

The  great  sciatic  nerve  and  its  two  primary  popliteal  branches  are 
continued  along  the  back  of  the  thigh  to  the  leg.  At  the  buttock  the 
ramifications  of  the  small  sciatic  nerve  como  mto  sight. 


1.  Obturator  nerve. 

2.  Posterior  articular  of  the  knee. 

3.  External  articular  of  the  knee. 

4.  Short  saphenous. 

5.  Branches  to  the  gastrocnemius. 

6.  Branch  to  the  soleus  muscle. 

7.  Peroneal  communicating  branch. 

8.  Nerve  to  short  head  of  the  biceps. 
f  9.  Branch  to  adductor  magnus. 

f    A.  second  branch  to  the  adduc- 
tor. 


10.  Muscular    branch    to    the    ham- 

strings. 

11.  Great  sciatic  nerve. 

13.  Internal  popliteal  trunk. 

13.  External  popliteal  trunk. 

14.  Small  sciatic  nerve. 

15.  Inferior  haemorrhoidal  nerve. 

16.  Inferior  pudendal  nerve. 


164:  ILLUSTRATIONS   OF   DISSECTIONS. 

Hhe  great  sciatic  nerve,  11,  takes  origin  in  fclie  sacral  plexus  (p.  71); 
and  after  passing  the  buttock,  it  is  continued  along  the  back  of  the  thigh 
as  far  as  midway  between  the  hip  tod  knee-joints,  where  it  bifurcates 
into  internal  and  external  popliteal.  In  this  course  the  nerve  is  covered 
above  by  the  gluteus  maximus,  and  thence  by  the  biceps,  so  that  it  is  not 
superficial  in  any  part.  It  rests  on  the  adductor  magnus,  and  lies  along 
the  outer  side  of  the  semimembranosus.  The  point  of  splitting  of  the 
nerve  reaches  sometimes  nearei  the  knee,  at  other  times  it  takes  jolace 
close  to  the  origin  from  the  sacral  plexus,  one  piece  piercing  the  fibres  of 
the  pyriformis  muscle. 

Its  branches  are  furnished  to  the  neighboring  muscles,  viz.  to  the  ham- 
strings and  the  great  adductor. 

The  branch  to  the  hamstrings,  10,  leaves  the  upper  part  of  the  trunk 
in  the  thigh,  and  subdivides  into  pieces  which  enter  the  semitendinosus, 
semimembranosus,  and  the  heads  of  the  biceps.  Occasionally  some  of 
those  offsets  arise  as  separate  branches  from  the  nerve-trunk. 

Branch  to  the  adductor  magnus,  9.  This  sj)rings  from  the  great 
sciatic  below  the  others,  and  sinks  into  the  fleshy  fibres  about  the  middle 
of  the  muscle;  but  it  is  small  in  comjDarison  with  the  size  of  the  adductor, 
because  the  muscle  is  sujjplied  mainly  by  the  obturator  nerve  (p.  133). 
A  second  nerve,  f ,  penetrates  the  fibres  near  the  inner  border. 

The  internal  iwpliteal  nerve,  12,  is  the  larger  of  the  two  trunks  derived 
from  the  great  sciatic,  and  is  directed  to  the  back  of  the  leg.  It  is  con- 
tinued through  the  middle  of  the  ham,  and  retains  the  name  popliteal  as 
far  as  the  lower  border  of  the  popliteus.  At  the  upper  part  of  the  ham 
it  is  placed  outside  the  line  oi  the  bloodvessels,  but  it  gradually  approaches 
these  near  the  knee,  and  conceals  them  at  the  lower  point  of  the  space. 
Its  offsets  are  furnished  to  the  knee-joint,  and  to  the  teguments  and  some 
muscles  of  the  back  of  the  leg:  most  of  them  are  now  seen  at  their  ori- 
gin. 

Articular  branches.  The  posterior,  2,  arises  near  the  top  of  the  ham, 
and  runs  beneath  the  trunk  of  the  nerve  and  the  popliteal  vessels  to  the 
back  of  the  knee-joint:  piercing  the  posterior  ligament,  it  ends  in  the 
synovial  membrane. 

Another  branch,  lower  internal  (Plate  liv.),  united  with  the  preceding 
or  leaving  the  nerve  below  it,  passes  under  the  trunks  of  the  bloodvessels, 
and  accompanies  the  lower  internal  articular  artery  to  the  joint. 

Branches  of  the  gastrocnemius,  5.     Each  head  of  the  muscle  receives 


GREAT    SCIATIO    NEKVE.  165 

a  separate  nerve,  and  the  branch  to  the  outer  head  supjolies  an  offset  to 
the  phmtaris  muscle. 

Branch  to  the  soleus,  6.  A  rather  large  nerve,  it  passes  under  the 
gastrocnemius,  and  enters  the  top  of  the  soleus  (Plate  liv.). 

The  sho7't  sajjJienotis,  4,  is  a  nerve  for  the  teguments:  it  lies  on  the 
popliteal  trunk,  and  then  courses  over  the  gastrocnemius,  to  become  cuta- 
neous below  the  calf  of  the  leg  (Plate  liii.). 

The  external  popliteal  nerve,  13,  whilst  contained  in  the  ham  lies  un- 
der cover  of  the  biceps  muscle;  but  it  leaves  the  space  ojDposite  the  level 
of  the  knee-joint,  and  proceeds  behind  the  tendon  of  the  same  muscle  to 
a  little  below  the  head  of  the  fibula,  where  it  ends  in  branches  for  the 
front  of  the  leg.  In  the  part  of  its  course  beyond  the  space  it  is  very 
superficial,  resting  on  the  gastrocnemius  and  soleus,  and  being  covered 
by  the  integuments  and  fascia  of  the  limb:  here  the  nerve  may  be  struck 
by  a  blow  or  injured  by  a  wound,  whilst  higher  up  it  is  protected  by  the 
overhanging  biceps,  which  will  serve  also  as  a  guide  to  its  position. 

No  muscular  branch  is  furnished  to  the  back  of  the  leg,  but  like  the 
other  popliteal  nerve  it  gives  an  articular  offset  to  the  knee,  and  cutane- 
ous to  the  back  of  the  leg. 

The  external  articular  irancli,  3,  leaves  the  parent  trunk  high  up  in 
the  popliteal  space,  and  descends  under  cover  of  the  biceps  muscle  nearly 
to  the  condyle  of  the  femur;  at  this  spot  it  meets  the  upper  external  arti- 
cular artery,  and  accompanying  this  to  the  outer  side  of  the  knee,  divides 
into  two  pieces  for  the  joint. 

The  peroneal  communicating  hranch,  7,  is  very  variable  in  size,  and 
pierces  the  deep  fascia  near  the  upper  23art  of  the  calf  of  the  leg;  to  the 
integuments  it  distributes  offsets,  and  joins  the  short  saphenous  nerve 
(Plate  LIII.). 

Obturator  nerve,  1.  The  articular  branch  of  this  nerve  begins  on  the 
fore  part  of  the  thigh  (Plate  xlvii.),  and  reaches  the  ham  by  perforating 
the  adductor  magnus  near  the  opening  for  the  femoral  vessels.  It  is  then 
directed  along  the  popliteal  vein  and  artery,  supplying  offsets  to  them,  as 
far  as  the  intercondyloid  hollow  of  the  femur;  here  it  quits  the  artery  on 
the  inner  side,  and  enters  the  joint  by  piercing  the  posterior  ligament. 

Small  sciatic  nerve,  14.  In  the  first  two  Plates  of  the  dissection  of 
the  buttock  this  nerve  has  been  more  completely  depicted  than  m  this 
Figure.     The  origin  and  separation  of  the  branches  at  the  lower  border 


166 


ILLUSTRATIONS    OF   DISSECTIONS. 


of  the  gluteus  maximus  are  visible,  but  most  of  the  limb-branches  have 
been  cut  through  near  their  beginning. 


DESCRIPTIOIf  OF  PLATE  LIII. 


The  cutaneous  vessels  and  nerves,  and  the  superficial  muscle  of  the 
back  of  the  leg,  are  represented  in  this  Illustration. 

The  skin  is  to  be  reflected  by  means  of  a  median  longitudinal  incision 
along  the  back  of  the  leg,  from  four  inches  above  the  knee-joint  to  the 
sole  of  the  foot,  with  a  transverse  cut  at  each  end  of  it.  In  the  fat  which 
then  appears  the  superficial  nerves  and  vessels  may  be  found  in  the  situa- 
tions pointed  out  in  the  Figure;  though  the  short  saphenous  nerve  does 
not  come  through  the  deep  fascia  till  half  way  along  the  leg. 


CUTANEOUS  NERVES  OF  THE  BACK  OF  THE  LEG. 

The  tegumentary  nerve-branches  on  the  back  of  the  leg  are  derived 
from  the  popliteal  trunks,  and  from  the  small  sciatic  and  anterior  crural 
nerves. 


1.  Inner  branch  of  the  internal  cuta- 

neous of  the  thigh. 

2.  Internal  or  long  saphenous. 

3.  Small  sciatic. 

4.  External  or  short  saphenous. 


5.  Peroneal  communicating  branch. 

6.  Cutaneous    branch    of    the    outer 

part  of  the  leg. 

7.  Internal  popliteal  nerve. 

8.  External  popliteal  nerve. 


Internal  cutaneous  of  the  thigh.  The  inner  branch  of  this  nerve,  I, 
becomes  cutaneous  close  above  the  knee-joint,  and  descending  over  the 
inner  belly  of  the  gastrocnemius,  reaches  about  half  way  to  the  heel. 
Near  the  knee  it  is  joined  by  a  small  branch  from  the  internal  saphe- 
nous. 

Internal  or  long  saphenous  nerve,  2,  escapes  from  beneath  the  sartorius 
on  the  inside  of  the  knee;  piercing  then  the  deep  fascia,  it  enters  the 
subcutaneous  fatty  layer,  and  accompanies  the  vein  of  the  same  name  to 


PLATE  Lll 


SUPERFICIAL   VESSELS    OF   THE    LEG. 


167 


the  inner  side  of  the  foot.  A  small  communicating  branch  unites  it  and 
the  internal  cutaneous. 

The  small  sciatic  nerve,  3,  passing  through  the  ham,  pierces  the  deep 
fascia  below  that  space.  When  cutaneous,  it  is  applied  to  the  short  saphe- 
nous vein,  and  sending  offsets  around  the  vessel,  is  continued  to  the  middle, 
or  the  lower  third  of  the  leg.  Inferiorly  it  unites  with  an  offset  of  the 
short  saphenous  nerve. 

The  external  or  short  saphenous  nerve,  4,  coming  from  the  internal 
popliteal  trunk  (p.  165),  courses  along  the  back  of  the  leg  and  below  the 
outer  ankle,  with  the  vein  of  the  same  name,  to  the  outer  side  of  the  foot 
and  little  toe.  In  this  course  it  lies  beneath  the  deep  fascia  till  about 
half  Avay  down  the  leg,  where  it  enters  the  fat,  and  is  joined  by  the  pero- 
neal communicating  branch,  5.  It  distributes  offsets  to  the  integuments 
of  the  leg  below  the  calf,  and  many  branches  of  large  size  to  the  outer  side 
of  the  heel  and  foot. 

Tlh.e  2)eroneal  communicating  branch,  b,  \&  derived  from  the  external 
popliteal  nerve:  appearing  superficial  to  the  fascia,  it  joins  the  short 
saphenous  as  soon  as  this  becomes  cutaneous.  To  the  outer  side  of  the 
leg  it  furnishes  a  considerable  cutaneous  branch,  6,  which  reaches  two- 
thirds  or  more  of  the  distance  to  the  heel:  this  branch  may  arise  sepa- 
rately from  the  external  popliteal  trunk. 

One  or  two  other  cutaneous  nerves  for  the  upper  and  outer  part  of  the 
leg  are  supplied  by  the  external  popliteal  nerve. 


SUPERFICIAL  VESSELS  OF  THE  BACK  OF  THE  LEG. 

Both  cutaneous  arteries  and  veins  are  found  with  the  cutaneous  nerves 
at  the  back  of  the  leg. 


Arteries. 

a.  Trunk  of  the  popliteal. 

6.  Muscular  branch  of  popliteal. 

c.  Cutaneous     branch     with     short 

saphenous  nerve. 

d.  Cutaneous  branch  with  peroneal 

communicating  nerve. 

e.  Cutaneous  part  of  the  anastomotic 

artery. 


Veins. 

g.  Trunk  of  the  popliteal. 

h.  Internal  or  long  saphenous. 

i.-  External  or  short  saphenous. 

j.   Communicating    branch  between 

saphenous  veins. 
k.  Communicating  to  saphenous  from 

posterior  tibial. 


168  ILLUSTRATIONS    OF    DISSECTIONS. 

Cutaneous  arteries.  Many  of  these  perforate  the  deep  fascia  at  inter- 
vals, and  some  pierce  the  gastrocnemius;  but  the  longest  and  largest 
accompany  the  superficial  veins. 

The  branch,  c,  with  the  short  saphenous  nerve  springs  from  the  pop- 
liteal trunk  Hear  the  knee-joint,  and  accompanies  the  vein  beneath  the 
fascia  to  reach  the  integuments. 

The  hranch,  d,  with  the  peroneal  communicating  nerve  begins  in  a 
muscular  branch  of  the  popliteal  trunk,  and  runs  with  an  offset  of  the 
nerve  to  the  integuments  of  the  outer  part  of  the  calf. 

A  hranch  with  the  small  sciatic  nerve  is  supplied  from  the  muscular 
q,rtery,  Z»,  and  reaches  the  integuments  below  the  upper  third  of  the  leg. 

The  cutaneous  branch,  e,  of  the  anastomotic  appears  at  the  knee;  it 
escapes  from  beneath  the  sartorius,  and  is  continued  onwards  with  the  in- 
ternal saphenous  nerve. 

Suinrficial  veins.  Two  in  number,  and  named  saphenous,  they  begin 
on  the  dorsum  of  the  foot — one  on  the  outer,  and  the  other  on  the  inner 
side. 

The  internal  saphenous,  h,  the  larger  of  the  two,  appears  only  for  a 
short  distance  on  the  inner  side  of  the  knee  and  calf  of  the  leg.  Upwards 
it  is  prolonged  to  the  thigh,  and  downwards  it  is  continued  to  the  foot 
with  the  nerve  of  the  same  name.  At  the  knee  it  is  joined  by  branches 
from  the  deep  veins. 

The  external  or  short  saphenous,  i,  begins  on  the  outer  side  of  the  foot 
in  the  venous  arch  on  the  dorsum  (Plate  lviii.).  Bending  below  the 
outer  ankle,  it  ascends  in  the  teguments  along  the  outer  border  of  the 
tendo  Achillis,  and  the  middle  line  of  the  calf  of  the  leg  to  the  popliteal 
space,  where  it  ends  by  joining  the  popliteal  vein.  In  the  lower  half  of 
the  leg  it  lies  with  the  short  saphenous  nerve,  and  in  the  upper  half  with 
the  small  sciatic  nerve.  About  the  foot  and  heel  it  receives  many 
branches  both  superficial  and  deep;  higher  in  the  leg  it  is  joined  by 
branches  from  the  teguments  and  deeper  parts,  and  communicates  with 
the  internal  saphenous  vein — one  of  the  last  set  of  branches  being  marked 
with  j. 


POPLJLTEAL    VE8SKLS    AND    NERVES. 


169 


MUSCLES  OF  THE  BACK  OF  THE  LEG. 

The  superficial  layer  of  muscles,  forming  the  projection  of  the  calf,  is 
delineated  in  this  and  the  following  Plate.  In  the  Illustration  a  view  of 
the  undisturbed  condition  of  the  popliteal  space  is  also  obtained. 


A.  Biceps  crui'is. 

B.  Semimembranosus. 

C.  Semitendinosus. 

D.  Sartorius. 

F.  Inner  head  of  the  gastrocnemius. 


G.  Plantaris,  belly  of  the  muscle. 
H.  Outer  head  of  gastrocnemius. 
I.   Tendon  of  the  plantaris. 
J.  Soleus  muscle. 
K.  Tendo  Achillis. 


Popliteal  space.  In  this  Figure  the  intermuscular  hollow  is  repre- 
sented as  it  appears  in  form  and  size  before  the  lateral  boundaries  are 
disturbed.     In  Plate  li.  the  space  is  shown  as  it  is  usually  described. 

As  now  seen  the  ham  measures  about  three  inches  in  length,  and  one 
and  a  half  in  width  at  the  widest  part;  and  its  diminished  size  is  due  to 
the  approximation  of  the  biceps,  A,  and  semimembranosus,  B,  over  the 
hollow.  Like  the  axilla,  the  space  extends  largely  under  the  muscles, 
though  it  has  but  a  comparatively  small  surface  opening;  and  it  is  pro- 
longed upwards  between  the  femur  and  the  hamstrings.  Tumors  in  the 
space,  projecting  under  the  muscles  bounding  laterally  the  ham,  would 
not  be  recognized  with  facility  in  consequence  of  the  fleshy  coverings  over 
them. 

Vessels.  In  the  undisturbed  state  of  the  ham  the  popliteal  vessels 
are  laid  bare  only  for  a  very  short  distance.  About  an  inch  of  the^o^- 
liteal  artery,  a,  is  visible — the  part  opposite  the  condyle  of  the  femur, 
which  comes  from  beneath  the  semimembranosus,  and  disappears  under 
the  inner  head  of  the  gastrocnemius. 

A  muscular  branch,  h,  leaves  the  trunk  of  the  artery  here,  and  sup- 
plies the  biceps  and  semimembranosus:  this  furnishes  a  cutaneous  offset 
with  the  small  sciatic  nerve. 

About  two  inches  of  the  popliteal  vein  can  be  seen  lying  external 
to  and  in  contact  with  the  artery:  at  this  spot  the  short  saphenous  vein 
opens  into  it. 

Nerves.  Very  unequal  parts  of  the  popliteal  nerves  appear  in  the 
hollow  of  the  ham  before  the  muscles  are  drawn  apart  from  each  other. 


170  ILLUSTBATIONS    OF    DISSECTIONS. 

About  three  inches  of  the  internal  pojDliteal  trunk  is  uncovered;  but 
strictly  speaking  only  an  inch  of  the  external  popliteal,  for  the  greater 
part  of  the  nerve  here  delineated  lies  out  of  the  ham,  and  rests  on  the 
gastrocnemius  and  soleus  muscles. 

Muscles  of  the  calf  of  tlie  leg.  Three  muscles  form  the  calf  of  the  leg, 
viz.,  gastrocnemius,  soleus,  and  plantaris,  but  only  the  first  is  illustrated 
in  this  Figure. 

The  gastrocnemius,  the  most  superficial  of  the  muscles  of  the  calf, 
consists  of  two  halves  or  bellies,  F  and  H,  which  unite  below  in  a  com- 
mon tendon. 

The  inner  half  of  the  muscle  is  attached  above  by  tendon  to  the  pos- 
terior part  of  the  inner  condyle  of  the  femur,  and  by  fleshy  fibres  to  the 
condyloid  line  for  about  an  inch.  And  the  outer  belly  is  fixed  also  by 
tendon  to  the  outer  condyle  of  the  femur,  viz.  to  the  upper  and  hinder 
part,  but  chiefly  to  an  impression  on  the  outer  surface.  Fleshy  fibres 
soon  succeed  to  each  tendon  of  attachment,  and  descend,  forming  sepa- 
rate bellies  (inner  and  outer),  to  end  in  the  wide  common  tendon. 

The  common  tendon,  broad  and  thin  above,  where  it  receives  the 
gastrocnemius,  becomes  narrower  below,  and  joins  that  of  the  soleus  in 
the  tendo  Achillis,  K:  from  it  a  slender  piece  is  prolonged  upwards  be- 
tween the  halves  of  the  muscle. 

The  muscle  is  in  contact  by  one  surface  with  the  fascia  of  the  leg;  and 
by  the  other  with  the  soleus  and  plantaris,  and  the  popliteal  vessels  and 
the  internal  popliteal  nerve.  The  inner  half  or  belly  is  more  prominent 
than  the  outer,  and  reaches  lower  down  the  leg.  At  its  origin  the  two 
parts  of  the  muscle  limit  laterally  the  popliteal  space. 

In  extension  of  the  ankle  the  muscle  is  always  combined  with  the 
soleus  through  the  tendo  Achillis;  but  from  its  attachment  to  the  femur 
it  possesses  a  power  of  moving  that  bone,  which  is  not  shared  by  the 
soleus.  Supposing  the  foot  fixed,  the  gastrocnemius  can  draw  back  and 
down  the  femur,  bending  the  knee-joint  at  the  same  time,  as  is  exempli- 
fied in  stooping  to  the  ground,  or  in  squatting.  In  walking  backwards  it 
will  assist  the  soleus,  the  knee-joint  being  kept  straight  by  the  extensors, 
in  bringing  the  limb  over  the  projected  foot. 


PLATE  LIV, 


MUSCLES    OF    THE    CALF    OF    THE    LEG. 


171 


DESCRIPTION  OF  PLATE  LIV. 


The  soleus  and  plantaris  muscles,  and  the  lower  part  of  the  popliteal 
vessels  and  nerves,  are  laid  bare  in  this  view. 

On  cutting  through  the  heads  of  the  gasbrocnemius  opposite  the  knee- 
joint,  and  removing  that  muscle  as  far  as  the  common  tendon,  the  sub- 
jacent muscles,  vessels,  and  nerves,  will  be  displayed  as  soon  as  the  fat 
and  areolar  tissue  have  been  removed. 


MUSCLES  OF  THE  CALF  OF  THE  LEG. 

The  deeper  muscles  of  the  calf,  viz.,  the  soleus  and  plantaris,  cover 
the  bones  of  the  leg;  and  above  these,  at  the  back  of  the  knee-joint,  lies 
the  popliteus — one  of  the  deep  layer  of  muscles. 


A.  Biceps  cruris. 

B.  Semimembranosus. 

C.  Semitendinosus. 

D.  Sartorius. 

F.  Inner  head  of  gastrocnemius. 


G.  Plantaris. 

H.  Outer  head  of  gastrocnemius. 

I.   Popliteus. 

J.   Soleus. 

K.  Tendo  Achillis. 


The  plantaris,  Gr,  possesses  a  short  rounded  belly,  from  three  to  four 
inches  long,  and  a  narrow,  slender  tendon,  the  longest  in  the  body.  Th« 
muscle  arises  by  fleshy  fibres  from  the  outer  condyloid  ridge  of  the  fe- 
mur, above  the  attachment  of  the  outer  head  of  the  gastrocnemius.  Op- 
posite the  upper  edge  of  the  soleus  the  fibres  end  in  the  tendon,  which  is 
prolonged  between  the  gastrocnemius  and  soleus  and  along  the  tendo 
Achillis,  to  be  inserted  into  the  back  of  the  os  calcis  at  the  inner  side  of, 
or  with  that  tendon. 

At  its  origin  the  muscle  appears  inside  the  external  head  of  the  gas- 
trocnemius, and  forms  part  of  the  outer  boundary  of  the  popliteal  space. 
As  far  as  half  way  down  the  leg  it  is  covered  by  the  gastrocnemius;,  but 
where  this  muscle  ends  in  a  tendon  the  plantaris  becomes  cutaneous,  and 
then  lies  along  the  inner  border  of  the  tendo  Achillis. 


172  ILLUSTRATIONS   OF   DISSECTIONS. 

Its  action  though  slight  is  similar  to  that  of  the  gastrocnemius,  for  if 
the  foot  is  unsupported  it  will  extend  the  ankle;  or,  the  foot  being  fixed, 
it  will  help  to  bend  the  knee,  as  in  stooping. 

The  soleus,  J,  the  deepest  muscle  of  the  calf,  is  named  from  its  flat- 
tened and  widened  form.  It  is  attached  to  both  bones  of  the  leg,  viz. ,  to 
the  head  and  upper  third  (sometimes  half)  of  the  posterior  surface  of  the 
fibula,  to  the  oblique  line  across  the  posterior  surface  of  the  tibia,  as  well 
as  to  the  middle  third  of  the  hinder  border  of  this  bone.  And  between 
the  two  bones  it  is  connected  with  a  tendinous  band,  which  bridges  over 
the  popliteal  vessels  and  nerves.  About  midway  between  the  knee  and 
the  heel  the  fleshy  fibres  end  in  a  tendon,  which  blends  with  that  of  the 
gastrocnemius. 

On  the  cutaneous  surface  rest  the  plantaris  and  gastrocnemius;  and 
underneath  the  soleus  are  the  deep  muscles  of  the  leg,  with  the  main 
bloodvessels  and  nerve  of  the  limb.  The  fibular  attachment  is  thick  and 
fleshy,  and  the  tibial,  thinner  than  the  other,  is  aponeurotic  on  the  under 
surface  (Plate  lv.).  Parallel  to  the  upper  border  is  the  popliteus  mus- 
cle, I. 

The  Tendo  AchiUis,  K,  is  formed  by  the  union  of  the  aponeuroses  of 
the  gastrocnemius  and  soleus  about  half  way  down  the  leg.  At  its  upper 
end  it  measures  about  three  inches  in  width,  and  is  thin,  but  it  gradually 
tapers  downwards,  becoming  thicker  and  rounded  near  the  heel;  and 
finally  it  is  inserted  by  a  somewhat  widened  part  into  the  lower  half  of 
the  posterior  surface  of  the  os  calcis.  In  Plate  lv.  a  bursa  is  shown, 
separating  the  tendon  from  the  upper  part  of  the  bone.  Comparatively 
superficial  throughout,  it  is  covered  only  by  the  teguments  and  the  deep 
fascia;  and  along  the  outer  side,  below,  are  placed  the  short  saphenous 
vein  and  nerve. 

In  deformity  of  the  foot  with  elevation  of  the  heel,  division  of  the 
tendon  is  needful  to  allow  the  os  calcis  to  be  put  in  contact  with  the 
ground.  In  the  execution  of  this  operation  the  cutting  instrument  is  en- 
tered beneath  the  tendon  about  an  inch  above  the  heel,  and  on  the  inner 
side;  and  the  tendon  being  put  on.  the  stretch  by  forcible  flexion  of  the 
ankle,  the  knife  is  carried  outwards  through  it  with  a  sawing  movement, 
care  being  taken  not  to  divide  the  integuments  as  the  last  part  of  the 
tendon  is  cut  through. 

Sometimes  the  tendon  is  ruptured  across  in  the  living  body  by  the 
forcible  and  sudden  action  of  the  fleshy  fibres.     When  this  accident  hap- 


LOWJPR    PART    OF    THE    POPLITEAL    VESSELS. 


173 


pens,  the  broken  ends  are  separated  widely,  the  upper  fragment  being 
raised  by  the  contraction  of  the  fleshy  bellies,  and  the  lower  piece  being 
depressed  by  the  descent  of  the  os  calcis  through  flexion  of  the  ankle. 
With  the  view  of  approximating  the  ends,  the  heel  should  be  raised  by 
forced  extension  of  the  ankle,  and  the  knee  should  be  bent  to  relax  the 
gastrocnemius;  by  the  adoption  of  the  position  here  indicated,  the  upper 
end,  which  is  liable  to  the  greatest  displacement,  may  be  more  readily 
depressed  towards,  and  retained  near  the  lower  fragment  by  a  bandao-e 
on  the  leg. 

Use  of  the  gastrocnemius  and  soleus.  These  muscles  raise  the  os 
calcis,  and  in  this  way  extend  the  ankle.  Should  the  toes  rest  on  the 
ground,  so  as  to  render  the  foot  immovable,  the  muscles  can  still  raise 
the  heel  with  the  weight  of  the  body,  as  in  the  different  kinds  of  progres- 
sion, or  in  standing  on  the  toes. 

If  the  lower  attachment  becomes  the  fixed  point  the  soleus  can  render 
the  leg-bones  steady  on  the  foot,  and  the  gastrocnemius  and  plantaris 
will  support  the  knee-joint,  as  in  the  straightened  state  of  the  limb  in 
standing.  During  stooping  to  the  ground  the  gastrocnemius  and  plantaris 
will  assist  in  bending  the  knee  ,  and  in  the  act  of  rising  from  that  posture 
the  soleus  brmgs  back  the  bones  of  the  leg  over  the  astragalus. 

Before  the  foot  reaches  the  ground  in  walking  backwards  the  muscles 
point  the  toes  ;  and  after  the  sole  touches  the  ground  they  incline  back 
the  slanting  limb  over  it. 


LOWER  PART  OF  THE  POPLITEAL  VESSELS. 

The  part  of  the  popliteal  vessels  here  referred  to  extends  beyond  the 
limits  of  the  ham,  and  is  laid  bare  by  reflecting  the  gastrocnemius. 


a.  Popliteal  artery. 

b.  Upper  muscular  branch. 

c.  Branch  to  inner  head  of  the  gas- 

trocnemius. 

d.  Branch  to  outer  head  of  the  gas- 

trocnemius and  the  plantaris. 


e.  Lower  external  articular  artery. 

/.  Lower  internal  articular  artery. 

g.  Branch  to  the  soleus. 

h.  Popliteal  vein. 

j.   Internal  saphenous  qein. 

k.  External  saphenous  vein,  cut. 


Popliteal  artei-y,  a.     The  part  of  this  artery  which  is  now  visible 
extends  from  the  knee-joint  to  the  lower  border  of  the  popliteus  muscle, 


174  ILLUSTRATIONS    OF    DISSECTIONS. 

I.  Covered  by  the  gastrocnemius  (now  reflected),  it  is  crossed  near 
the  ending  by  the  small  tendon  of  the  plantaris,  and  its  point  of  splitting 
into  the  tibials  is  concealed  by  the  soleus,  J.  Beneath  it  lies  the  pop- 
liteus,  I. 

Superficial  and  close  to  the  artery  is  the  popliteal  vein,  which  gra- 
dually inclines  inwards,  so  as  to  be  placed  altogether  inside  at  the  lower 
border  of  the  popliteus. 

The  internal  popliteal  nerve,  coursing  along  the  bloodvessel,  changes 
its  position  to  the  artery  in  the  same  manner  as  the  vein  ;  for  opposite 
the  back  of  the  knee-joint  it  lies  between  the  vessel  and  the  surface,  but 
is  internal  to  the  artery  at  the  lower  border  of  the  popliteus. 

Branches.  From  this  part  of  the  popliteal  arise  the  lower  muscular 
offsets,  and  the  lower  pair  of  articular  arteries. 

Loiver  muscular  tranches  are  furnished  to  the  muscles  of  the  calf,  viz., 
gastrocnemius,  soleus,  and  plantaris. 

Branches  to  the  gastrocnemius,  c  and  d.  Two  in  number,  they  are 
named,  commonly,  sural.  Th.e  artery,  c,  enters  the  inner  fleshy  belly  of 
the  muscle  ;  and  the  vessel,  d,  ramifying  in  the  outer  belly,  gives  a  small 
offset  to  the  plantaris. 

Branch  to  the  soleus  b.  Accompanying  the  nerve  of  the  same  name, 
it  pierces  the  upper  part  of  its  muscle  at  the  cutaneous  aspect. 

The  loiver  pair  of  articular  arteries  are  directed,  one  outwards,  the 
other  inwards,  to  the  front  of  the  knee-joint. 

The  outer,  e,  runs  above  the  head  of  the  fibula  and  beneath  the  exter- 
nal lateral  ligament  to  the  outer  part  of  the  keee,  where  it  anastomoses 
with  the  other  articular  arteries  over  the  joint. 

The  inner,  f,  lying  at  a  lower  level  than  its  fellow,  jDasses  beneath  the 
internal  lateral  ligament  to  the  inner  side  of  the  articulation,  and  termi- 
nates like  the  other.     A  small  articular  nerve  takes  the  same  course. 

T\\Q  popliteal  vein,  h,  begins  by  the  union  of  the  anterior  and  poste- 
rior tibial  veins  at  the  spot  where  the  artery  ends.  Internal  to  the  artery 
at  first,  it  becomes  afterwards  superficial,  and  ihen  external,  as  before 
said.  The  branches  joining  it  in  this  part  are  companions  to  those  of  the 
artery. 


POPLITEAL    KEKVE8. 


175 


POPLITEAL  NERVES. 


These  nerves  and  most  of  their  branches  have  been  ilkisfcrated  in  pre- 
ceding Plates,  but  some  of  the  muscular  offsets  of  the  internal  nerve  may 
be  now  observed  more  completely  after  the  removal  of  the  gastrocnemius. 


1.  Internal  popliteal  trunk. 

2.  External  popliteal  tnink. 

3.  Branch  to  inner  head  of  the  gas- 

trocnemius. 

4.  Branch  to  outer  head  of  the  gas- 

trocnemius. 


5.  Branch  to  the  plantaris. 

6.  Branch  to  the  soleus. 

7.  Lower  internal  articular  branch. 

8.  Short  saphenous  (origin). 

9.  Branch  to  the  popliteus. 

10.  Short  saphenous  (lower  end). 


Internal  liopliteal  trunk,  1.  The  muscular  branches  of  this  nerve 
are  furnished  to  the  muscles  of  the  calf  and  the  popliteus.  The  nerves 
to  the  superficial  muscle  of  the  calf,  viz.,  gastrocnemius,  have  been  he- 
fore  noticed  (Plate  liii.). 

The  hrancli  to  the  plantaris  muscle,  5,  is  an  offset  of  the  nerve  to  the 
outer  head  of  the  gastrocnemius;  it  enters  the  fleshy  fibres  of  its  muscle 
with  a  small  twig  of  an  artery. 

The  Irancli  to  the  soleus,  6,  descends  beneath  the  gastrocnemius,  and 
divides  into  pieces  which  penetrate  the  muscle  near  the  upper  attach- 
ment to  the  bones  of  the  leg,  and  at  the  sujoerficial  aspect. 

The  Iranch  to  the  j^opliteus,  9,  arises  opposite  the  knee-joint,  and 
passes  beneath  the  i^lantaris  to  the  lower  border  of  its  muscle:  at  this 
point  it  bends  round  the  edge  of  the  popliteus,  and  enters  the  under  sur- 
face. 

Lower  internal  articular  nerve,  7,  which  is  shown  at  its  origin  in 
Plate  Lii.,  appears  from  beneath  the  popliteal  vessels,  and  passes  along 
the  upper  border  of  the  popliteus  muscle  with  the  artery  of  the  same 
name;  it  then  runs  beneath  the  internal  lateral  ligament  to  the  fore  part 
of  the  knee,  where  it  jiierces  the  cajDsule  of  the  joint. 

External  popliteal  trunk,  %.  Nearly  the  same  view  of  this  nerve  is 
given  in  this  as  in  the  preceding  Plate.  Inferiorly  it  passes  beneath  the 
peroneus  longus,  and  divides  between  that  muscle  and  the  fibula  into  its 
terminal  branches  for  the  fore  part  of  the  leg,  viz.,  recurrent  articular, 
musculo-cutaneous,  and  anterior  tibial. 


176 


LLLUSTEATIO^'S    OF    DISSECTIONS. 


DESCPvIPTIOX  OF  PLATE  LY. 


The  deep  muscles,  vessels,  and  nerves  of  the  back  of  the  leg  are  ex- 
hibited in  this  Plate. 

The  dissection  for  this  view  will  be  prepared  by  reflecting  the  muscles 
of  the  calf,  and  removing  the  fascia  and  fat  which  then  come  into  sight. 
An  aponeurosis  covering  the  central  muscle  is  to  be  divided  longitudinally, 
and  to  be  thrown  inwards  and  outwards  with  fibres  of  the  two  lateral  mus- 
cles attached  to  it. 


DEEP  ilUSCLES   OF  THE   BACK   OF   THE  LEG. 

In  this  D-ronp  there  are  four  muscles:  three  are  prolonged  to  the  foot 
and  extend  the  ankle  as  they  pass  by;  and  the  fourth,  crossing  behind  the 
knee,  flexes  this  joint. 


A.  Popliteus. 

B.  Fibular  origin  j 


^    ^.,  .  ,      .    .        ,' of  the  soleus. 

C.  Tibial  ongm     ) 

D.  Flexor  longus  pollicis. 

E.  Flexor  longus  digitorum. 


F.  Tibialis  posticus. 

G.  Tendo  AchUlis,  cut. 

H.  Peroneal    muscles    covered     by 
fascia. 


The  popliteus  muscle,  A,  intervenes  between  the  contiguous  ends  of 
the  femur  and  tibia,  crossing  behind  the  knee-joint.  It  arises  within  the 
capsule  of  the  joint  by  a  tendon  which  is  fixed  to  the  fore  part  of  a  groove 
on  the  outer  condyle  of  the  femur;  and,  outside  the  capsule,  by  fleshy 
fibres  attached  to  the  posterior  ligament.  The  muscle  is  thin  and  fleshy, 
and  is  inserted  below  the  head  of  the  tibia,  into  an  impression  on  the 
posterior  surface  of  the  bone. 

A  special  aponeurosis  covers  the  muscle,  and  separates  it  from  other 
parts.  Towards  the  surface  the  popliteus  is  concealed  by  the  gastrocne- 
mius  and  plantaris;  and  is  crossed  by  the  popliteal  vessels  and  the  internal 
popliteal  nerve.  Beneath  it  is  the  tibio-peroneal  joint  with  the  upper 
end  of  the  tibia.     Along  part  of  the  upper  border  run  the  lower  internal 


PLATE  LV 


h    ,,n 


fle;xor  muscles  of  the  digits.  177 

articular  vessels  and  nerves;  and  contiguous  to  the  lower  edge  is  the  so- 
leus  muscle.  The  tendon  of  origin  within  the  capsule  of  the  knee  is 
surrounded  by  tlic  synovial  membrane  in  the  same  way  as  the  biceps  is 
incased  in  the  shoulder-joint. 

By  the  contraction  of  the  muscle  the  tibia  will  be  moved  backwards 
towards  the  femur,  producing  flexion  of  the  knee;  and  after  the  joint  has 
been  bent  the  popliteus  can  turn  in  the  tibia,  so  as  to  give  rise  to  rotation 
inwards  of  the  foot. 

The  flexor  longus  poUicis,  D,  is  the  most  external  of  the  three  mus- 
cles entering  the  foot.  Placed  over  the  fibula,  it  takes  origin  from  the 
posterior  surface  of  that  bone  below  the  soleus,  except  about  an  inch  in- 
feriorly;  its  fibres  are  further  attached  internally  to  an  aponeurosis 
covering  the  tibialis  posticus,  and  externally  to  the  fascia  separating  it 
from  the  peronei  muscles.  Near  the  ankle  the  muscle  ends  in  a  tendon, 
which  is  continued  to  the  foot  through  a  separate  compartment  in  the 
annular  ligament,  and  along  a  groove  in  the  astragalus;  its  further  course 
through  the  foot  to  the  great  toe  is  shown  in  Plate  lvi. 

The  upper  part  of  the  muscle  is  covered  by  the  soleus;  and  the  lower, 
which  lies  outside  the  tendo  Achillis,  is  in  contact  with  the  deep  fascia. 
The  muscle  rests  on  the  fibula,  its  length  of  attachment  to  the  bone 
varying  with  that  of  the  soleus,  and  it  conceals  in  part  the  tibialis  posticus. 
In  its  fibres  are  contained  the  peroneal  vessels.  By  the  outer  border  it  is 
contiguous  to  the  peronei  muscles,  only  fascia  intervening;  and  by  the  in- 
ner edge  it  touches  the  posterior  tibial  nerve  for  its  lower  two-thirds,  but 
this  connection  has  been  destroyed  by  the  displacement  of  the  muscle. 

"With  the  foot  hanging  the  first  action  of  the  muscle  will  be  employed 
in  bending  the  great  toe,  and  the  next  in  extending  the  ankle.  When 
the  foot  is  fixed  this  flexor  assists  the  special  extensors  of  the  ankle  in 
walking,  and  the  flexor  longus  digitorum  in  standing  on  the  toes. 

If  the  lower  end  of  the  muscle  becomes  the  fixed  point,  the  fibula, 
when  placed  in  front  of  the  astragalus,  will  be  brought  backwards  to  a 
right  angle  with  the  foot,  as  is  seen  in  rising  from  a  stooping  posture, 
and  in  walking  backwards. 

The  flexor  longus  digitorum,  E,  lies  on  the  tibia,  and  is  the  most  slen- 
der of  the  muscles  in  the  deep  layer  at  the  back  of  the  leg.  It  arises  from 
the  posterior  surface  of  the  tibia,  beginning  at  th«  attachment  of  the  so- 
leus, and  extending  to  three  inches  from  the  lower  end;  and  some  fibres 

are  connected  externally  to  the  aponeurosis  covering  the  tibialis.     Near 
12 


Its  ILLUSTRATIONS    OF    DISSECTIONS. 

the  ankle  the  muscle  ends  in  a  tendon,  which  passes  behind  that  of  the  tibi- 
alis through  a  separate  sheath  in  the  annular  ligament,  and  entering  the 
foot  ends  in  slips  for  the  four  outer  toes  (Plate  LVI.). 

In  the  log  this  flexor  is  placed  beneath  the  soleus  for  half  its  length, 
but  the  rest  of  the  muscle  projects  inside  the  tendo  Achillis  and  supports 
the  tibial  vessels.  By  the  under  surface  it  touches  the  tibia  as  far  as  to 
three  inches  from  the  inner  malleolus,  where  it  is  separated  from  that  bone 
by  the  intervention  of  the  tibialis  posticus.  Along  the  outer  edge  lie  the 
tibial  vessels  for  about  the  upper  half  of  its  length,  but  below  that  point 
it  projects  outwards  beyond  the  vessels. 

The  foot  being  movable  the  long  flexor  will  bend  the  four  outer  toes, 
and  extend  afterwards  the  ankle.  If  the  foot  rests  on  the  ground,  so 
that  the  toes  are  rendered  immovable,  the  muscle  will  be  united  in  its 
action  with  the  preceding  flexor  to  raise  the  weight  of  the  body,  as  in 
standing  on  the  toes,  or  in  walking. 

Supposing  the  tibia  placed  in  front  of  the  astragalus,  as  in  stooping, 
the  muscle  acting  from  below  will  assist  in  bringing  that  bone  to  a  right 
angle  with  the  foot. 

The  tibialis  posticus,  F,  is  the  central  muscle  of  the  deep  layer,  and 
covers  the  membrane  between  the  bones.  It  has  a  wide  origin  from  the 
interosseous  membrane,  the  tibia,  and  the  fibula; — viz.,  from  all  the 
membrane  except  an  inch  below;  from  a  special  surface  on  each  bone, 
which  is  contiguous  to  the  membrane,  and  reaches  down  as  far  as  two 
inches  from  the  malleolus;  and  some  fleshy  fibres  are  also  attached  to  the 
aponeurosis  covering  the  surface.  Inferiorly  the  muscle  passes  between 
the  tibia  and  the  flexor  longus  digitorum;  and  its  tendon  is  transmitted  to 
the  foot  through  the  inner  space  of  the  annular  ligament,  lying  in  the 
groove  in  the  inner  malleolus.  Its  insertion  into  the  scaphoid  and  other 
bones  of  the  foot  appears  in  Plate  lvii.,  Fig.  2. 

Situate  between  the  flexors  of  the  digits,  the  tibialis  is  covered  by  the 
thin  aponeurosis  which  is  fixed  into  the  leg-bones,  and  superficial  to  all 
is  the  soleus:  on  it  lie  the  tibial  vessels  and  nerve  for  the  upper  half. 
Beneath  it  is  the  interosseous  membrane.  Sujieriorly  there  is  an  inter- 
val between  its  attachments  to  the  bones,  through  which  the  anterior 
tibial  vessels  j^ass;  and  inferiorly  the  muscle  is  directed  inwards  beneath 
the  flexor  longus  digitorum. 

Should  the  foot  be  free  to  be  moved  the  tibialis  posticus  will  draw  it 
down  and  back  so  as  to  extend  the  ankle,  and  will  direct  inwards  the 


DEEP    VESSELS    OF    TxIE    BACK    OF    THE    LEG. 


179 


great  too.  If  tlie  foot  rests  on  tlie  ground,  the  mnscle  uniting  in  its  action 
with  the  tibialis  anticus  will  raise  the  inner  edge,  as  in  standing  on  the 
outer  border  of  the  foot. 

Wlien  the  bones  of  the  leg  slant  forwards,  as  in  stooping,  the  muscle 
taking  its  fixed  point  below  will  combine  with  the  deep  flexors  of  the 
digits  in  bringing  back  the  tibia  over  the  astragalus,  as  the  leg  is  straight- 
ened. 


DEEP  VESSELS  OF  THE  BACK  OF  THE  LEG. 

At  the  back  of  the  leg,  as  on  the  front  of  the  forearm,  the  main  artery 
of  the  limb  bifurcates  just  beyond  the  joint,  and  from  the  chief  of  the  two 
j)ieces  into  which  it  splits  is  given  a  third  artery,  so  that  in  each  member 
there  exists  one  leading  vessel  where  there  is  a  single  bone,  and  three 
where  there  are  two  bones. 


Arteries. 
a.  Popliteal  trunk. 
6.  Lower  and  external  articular. 

c.  Low^er  internal  articular. 

d.  Anterior  tibial  trunk. 

e.  Peroneal  trunk. 

/.  Continuation  of  peroneal. 
g.  Posterior  tibial  trunk. 


Veins. 
Jc.  Popliteal  trunk. 
Z.   Peroneal  venae  comites. 
n.  Venae  comites,  posterior  tibial, 
o.  Communicating     from     deep    to 

superficial  veins. 
p.  Internal  saphenous. 


The  anterior  tibial  artery,  d,  is  one  of  the  two  trunks  into  which  the 
popliteal  splits  at  the  lower  border  of  the  popliteus  muscle;  it  passes 
above  the  interosseous  membrane  to  the  front  of  the  leg,  and  its  anatomy 
is  illustrated  in  Plate  lviii. 

^\\Q  posterior  tiiial  artery,  g,  the  other  trunk  obtained  from  the  di- 
vision of  the  popliteal,  extends  to  the  sole  of  the  foot,  and  ends  in  the 
plantar  arteries.  It  is  limited  by  the  lower  border  of  the  popliteus  in  one 
direction,  and  by  the  lower  edge  of  the  internal  annular  ligament  in  the 
other.  On  the  surface  of  the  limb  its  position  would  be  indicated  by  a 
line  from  the  centre  of  the  knee-joint  to  a  point  midway  between  the 
heel  and  the  ankle.  The  upper  half  of  the  vessel  lies  deeply,  and  the 
lower  is  comparatively  superficial. 

Upper  half.  Placed  beneath  the  soleus,  as  is  seen  in  the  preceding 
Plate,  it  rests  on  the  tibialis  posticus,  F.     Close  to  it  internally  is  the 


180  ILLUSTRATIONS    OF    DISSECTIONS. 

flexor  longiis  digitorum,  and  lying  outside  it  near  the  termination  is  the 
flexor  longus  pollicis. 

Companion  veins  course  along  the  sides  of  the  artery,  and  join  across 
it  at  short  distance. 

The  large  posterior  tibial  nerve  lies  close  to  the  artery:  at  the  upper 
end  it  is  internal,  but  it  becomes  external  to  that  vessel  below  the  origin 
of  the  peroneal  artery;  and  it  keeps  afterwards  the  same  position. 

Lower  lialf.  Below  the  middle  of  the  leg  the  soleus  ends  in  a  tendon, 
and  the  artery,  gradually  inclining  inwards,  comes  to  lie  between  the  ten- 
don and  the  edge  of  the  tibia.  Here  it  is  covered  by  the  deep  fascia  and 
teguments,  and  lies  on  the  flexor  longus  digitorum  and  the  end  of  the 
tibia:  on  its  outer  side  is  placed  the  flexor  longus  pollicis  as  in  the  upper 
part. 

The  vense  comites  and  the  posterior  tibial  nerve  have  the  same  position 
to  the  lower  as  to  the  upper  half. 

Between  the  heel  and  the  ankle  the  artery  passes  under  the  internal 
annular  ligament,  and  over  the  ankle-joint;  and  it  divides  at  the  lower 
border  of  that  band  into  the  two  plantar  arteries.  Internal  to  it  at  this 
spot  lies  the  tendon  of  the  long  flexor  of  the  toes,  and  external  and 
nearer  to  it,  the  tendon  of  the  long  flexor  of  the  great  toe.  The  com- 
panion veins  and  nerve  have  the  same  position  as  above. 

Size  and  jjosition  of  the  hranclies.  ISTumeroas  small  branches,  chiefly 
muscular,  arise  at  intervals  along  the  artery;  but  about  one  inch  and  a 
half  from  the  beginning  springs  the  large  peroneal  trunk,  and  near  the 
ankle-joint  a  branch  of  intermediate  size  (communicating)  leaves  it. 

Ligature  of  the  artery.  In  the  living  body  the  artery  is  not  likely  to 
need  tying  except  in  the  case  of  a  wound  of  the  leg  or  foot,  and  reference 
will  be  afterwards  made  to  those  injuries;  but  the  placing  a  ligature  on 
the  vessel  in  the  dead  body  may  be  practised  in  both  the  upper  or  deep, 
and  the  lower  or  superficial  part. 

In  the  upper  half.  Where  the  posterior  tibial  is  covered  by  the  soleus 
it  may  be  reached  in  the  following  way: — A  longitudinal  incision  about 
four  inches  long  is  to  be  carried  through  the  integuments  and  deep  fascia 
at  the  distance  of  an  inch  behind  the  edge  of  the  tibia  :*  this  cut  should 

'  If  the  cut  is  made  near  the  edge  of  the  tibia,  with  the  view  of  separating  this 
muscle  from  the  bone,  as  is  sometimes  recommended,  the  student  is  apt  to  detach 
also  the  deep  flexor  of  the  toes,  and  to  experience  some  difficulty  in  finding  the 
interval  between  the  muscles. 


LIGATURE   OF   POSTERIOR   TIBIAL.  181 

lie  behind  the  internal  saphenous  vein,  and  near  the  edge  of  the  gastro- 
cnemius (Plate  liil).  Should  this  last  muscle  come  into  sight  it  is  to 
be  turned  aside,  and  the  solens,  which  then  appears,  is  to  be  cut  through 
for  the  whole  length  of  the  superficial  incision;  whilst  this  step  is  being 
executed  the  ankle  is  to  be  extended  with  the  view  of  relaxing  the  muscle, 
and  as  the  fleshy  fibres  are  divided  an  aponeurosis  on  the  under  surface 
shows  itself.  On  carefully  cutting  through  this  aponeurotic  part,  and  a 
thin  piece  of  the  deep  fascia  under  it,  the  bloodvessels  will  be  arrived  at 
immediately  beneath,  though  external  to  the  line  of  the  incision. 

To  find  the  artery,  look  for  the  posterior  tibial  nerve,  whjch  lies  on 
the  outer  side  of,  and  may  be  taken  as  the  deep  guide  to  the  vessel. 

Only  a  very  thin  sheath  incloses  the  vessels;  and  in  opening  and  de- 
taching it  care  should  be  taken  of  the  venae  comites. 

In  passing  the  ligature  let  the  aneurism  needle  be  moved  from  right 
to  left,  and  without  including  the  veins. 

Occasionally  no  artery  may  be  met  with,  for  it  may  be  wanting  in  this 
l^art  of  the  leg. 

In  the  lower  half.  Where  the  posterior  tibial  is  uncovered  by  muscle 
the  surface  line  before  given  will  serve  as  the  superficial  guide  to  its  posi- 
tion. A  cut  about  two  inches  and  a  half  long  is  to  divide  the  teguments 
in  that  line:  some  branches  of  the  internal  saphenous  vein  and  nerve  will 
probably  be  cut  through  in  this  stage,  but  the  knife  should  be  used  far 
enough  back  to  be  clear  of  the  trunk  of  the  vein.  Nextly  the  deep  fascia 
of  the  limb  is  to  be  incised  on  a  director  or  without,  according  to  the  skill 
of  the  operator. 

Beneath  the  fascia  the  posterior  tibial  nerve  may  be  recognized,  and  it 
will  serve  as  the  guide  to  the  artery  in  the  wound:  to  the  inner  side  of 
the  nerve  lie  the  bloodvessels. 

When  opening  the  sheath,  and  passing  the  thread  around  the  vessel, 
the  same  precautions  are  to  be  taken  as  in  ligature  of  the  artery  higher 
up. 

Wounds  of  the  artery  are  more  likely  to  happen  in  the  lower  part  of 
the  leg  where  the  vessel  is  near  the  surface  than  where  it  is  covered  by 
the  soleus  muscle.  If  the  injury  has  its  seat  in  the  lower  half  of  the  leg 
the  wound  may  be  enlarged,  and  two  ligatures  may  be  applied  to  the 
bloodvessels  so  as  to  arrest  the  flow  of  blood  from  each  end.  But  if  the 
artery  is  opened  through  the  soleus  the  depth  will  increase  greatly  the 
diflSculty  of  finding  the  bleeding  vessel  in  the  bottom  of  the  wound.     In 


182  ILLTJSTKATI0N8   OF   DISSECTIONS. 

this  case  some  surgeons  have  recommended  that  the  wound  should  be  en- 
larged, and  that  the  vessel  should  be  tied,  as  before  said;  but  others  would 
prefer  to  try  the  effect  of  pressure  applied  to  the  wound  and  the  main 
vessel  of  the  limb  before  undertaking  so  difficult  an  operation. 

Branches  of  the  posterior  tihial.  With  the  exception  of  the  large  pero- 
neal artery  the  other  branches  are  small  in  size. 

Muscular  branches  arise  from  both  sides  of  the  trunk  all  the  way  along: 
two  or  three  are  supplied  to  the  fibular  and  tibial  attachments  of  the 
soleus;  and  the  larger  of  these  pierces  the  tibial  part,  and  ramifies  on  the 
liead  of  tliQ  tibia  and  the  inner  side  of  the  knee-joint.  The  remaining 
offsets  enter  the  tibialis  posticus  and  the  flexors  of  the  digits. 

Cutaneous  offsets.  Some  small  branches  pierce  the  fascia  in  the  lower 
half  of  the  leg,  and  end  in  the  teguments  (Plate  liii.  ) :  one  or  two  of 
this  set  arising  near  the  ankle,  run  with  the  cutaneous  plantar  nerve,  7, 
to  the  sole  of  the  foot. 

Nutritious  of  the  shaft  of  the  tihia.  It  is  derived  from  one  of  the 
upper  muscular  branches,  and  pierces  the  fibres  of  the  tibialis  posticus  to 
enter  the  canal  on  the  posterior  surface  of  the  bone. 

A  communicating  Iranch  is  directed  transversely  outwards  across  the 
lower  end  of  the  tibia  to  join  with  a  like  offset  from  the  peroneal  artery; 
it  is  concealed  by  the  flexor  longus  pollicis. 

The  articular  branches  arise  from  the  artery  opposite  the  ankle-joint, 
and  are  distributed  to  that  articulation. 

The  venm  comites,  n,  of  the  posterior  tibial  artery  lie  on  the  sides  of 
that  vessel,  over  which  they  are  united  by  cross  pieces  ;  they  have  the 
same  extent  as  the  artery,  viz.,  from  the  foot  to  the  lower  border  of  the 
popliteus.  Above,  they  unite  with  the  anterior  tibial  veins  to  form 
the  popliteal  vein.  At  the  lower  part  of  the  leg  they  are  thick  and 
strong. 

The  peroneal  artery,  e,  is  the  largest  branch  of  the  posterior  tibial, 
and  arises  one  inch  and  a  half  from  the  beginning  of  that  trunk.  To 
reach  the  fibula,  it  passes  between  the  soleus  and  the  tibialis  posticus; 
and  it  is  then  continued  along  that  bone,  contained  in  the  fibres  of  the 
flexor  pollicis.  Much  diminished  in  size  at  the  lower  part  of  the  interos- 
seous membrane,  the  vessel,  /,  is  continued  behind  the  external  malleolus 
to  the  outer  side  of  the  heel;  here  it  ends  in  branches,  of  which  some 
supply  the  foot,  and  others  anastomose  with  offsets  of  the  posterior 
tibial,  and  external  plantar  and  tarsal  arteries. 


PERONEAL  ARTERY  AND  BRANCHES.  183 

Two  companion  veins  run  with  the  artery,  and  the  nerve  to  the  flexor 
pollicis  lies  on  it  oftentimes. 

Its  I) ranches  are  muscular  and  communicating,  but  they  are  concealed 
by  the  flexor  pollicis. 

Muscular  hranclies  enter  the  muscles  with  which  it  is  in  contact,  viz., 
soleus,  tibialis,  and  flexor  pollicis;  and  some  wind  round  the  outside  of 
the  fibula,  lying  in  grooves  in  the  bone,  to  reach  the  peronei. 

The  nutritive  artery  of  the  hone  is  furnished  by  one  of  the  muscular 
branches,  and  enters  the  aperture  in  the  shaft  of  the  fibula,  after  23iercing 
the  tibialis;  it  is  smaller  than  the  artery  to  the  shaft  of  the  tibia. 

Communicating  branches.  Two  in  numBer,  anterior  and  posterior, 
they  serve  the  purpose  of  anastomosing  with  the  anterior  and  posterior 
tibial  arteries. 

The  anterior  passes  to  the  front  of  the  leg,  through  an  aperture  \x\. 
the  lower  part  of  the  interosseous  membrane,  and  is  commonly  named 
anterior  ^peroneal.  It  is  continued  to  the  dorsum  of  the  foot  on  the  outer 
side,  and  some  of  its  offsets  anastomose  with  the  external  malleolar  and 
tarsal  arteries.  When  the  anterior  tibial  trunk  is  unusually  small,  or 
is  wanting  on  the  foot,  this  communicating  branch  is  proportionally 
augmented,  taking  the  place  of  the  deficient  artery  in  the  one  case,  and 
assisting  the  smaller  trunk  in  supplying  the  foot  in  the  other  condition. 

The  posterior  communicating  lies  beneath  the  flexor  pollicis,  opposite" 
the  lower  end  of  the  tibia,  and  unites  with  a  similar  branch  of  the  pos- 
terior tibial  (p.  183).  Sometimes  there  is  a  second  communicating  artery 
lower  down.  If  the  trunk  of  the  posterior  tibial  is  absent  in  the  lower 
part  of  the  leg,  this  branch  of  the  peroneal,  much  increased  in  size,  takes 
the  place  of  that  bloodvessel,  and  enters  the  sole  of  the  foot  to  supply 
the  plantar  arteries. 

The  companion  veins,  I  (vense  comites),  of  the  peroneal  artery  lie 
on  the  sides  of  that  vessel  and  communicate  across  it ;  they  receive 
branches  corresponding  with  the  offsets  of  the  artery,  and  end  above 
in  the  posterior  tibial  veins. 

The  posterior  tibial  nerve,  9,  is  a  continuation  of  the  internal  popli- 
teal trunk,  and  extends  from  the  lower  border  of  the  popliteus  muscle  to 
the  space  between  the  inner  malleolus  and  the  os  calcis,  where  it  divides 
near  or  beneath  the  annular  ligament  into  the  two  plantar  nerves.  Its 
connections  with  muscles  are  the  same  as  those  of  the  bloodvessel.  In 
close  contact  with  the  artery  throughout,  it  changes  its  place  with 


184  ILLUSTRATIONS    OF    DISSECTIONS. 

respect  to  the  vessel;  thus,  for  an  inch  and  a  half  it  lies  inside,  but 
thence  to  its  termination  outside  the  artery. 

Its  offsets  are  chiefly  supplied  to  the  contiguous  muscles,  but  it  gives 
a  cutaneous  nerve  to  the  sole  of  the  foot. 

The  muscular  tranches,  4,  5,  6,  enter  the  tibialis  posticus,  flexor  digi- 
torum,  and  flexor  pollicis ;  they  arise  at  intervals  along  the  nerve,  or 
sometimes  by  a  common  branch  from  the  internal  popliteal  trunk. 

A  cutaiieousjilantar  nerve,  7,  begins  above  the  os  calcis,  and,  dividing 
into  two  or  more  branches,  is  continued  beneath  the  fascia  and  the 
internal  annular  ligament,  nearly  to  the  sole  of  the  foot;  its  offsets, 
accompanied  by  small  arteries,  pierce  separately  that  ligament,  and  end 
in  the  teguments  of  the  under  part  of  the  heel  (Plate  lvi.). 

The  internal  saphenous  vein,  p,  begins  in  a  cutaneous  venous  arch  on 
the  dorsum  of  the  foot  (Plate  lviii.);  it  then  ascends,  crossing  the  tibia 
above  the  inner  ankle,  and  takes  afterwards  a  position  behind  the  pos- 
terior edge  of  that  bone  as  far  as  the  knee,  where  it  has  been  shown  pass- 
ing that  articulation  to  reach  the  thigh  (Plate  xliv.).  A  nerve  of  the 
same  name  accompanies  it. 

Many  superficial  branches  enter  it  in  this  course.  In  the  leg  it  com- 
municates with  the  deep  veins — anterior  and  posterior  tibial,  and  near 
the  knee  it  joins  an  internal  articular  vein.  In  the  Figure,  a  branch,  o, 
is  represented  uniting  with  the  posterior  tibial  veins. 

The  iyiternal  saphenous  nerve,  8,  accompanies  the  vein  of  the  same 
:;"ame  to  the  inner  side  of  the  foot,  where  it  ends  about  the  middle  of 
the  tarsus,  as  may  be  seen  in  Plate  Lviii.  In  the  leg  it  furnishes  many 
collateral  cutaneous  offsets,  both  forwards  over  the  tibia  and  front  of  the 
limb,  and  backwards  behind  but  near  that  bone. 


DESCRIPTIOJf  OF  PLATE  LVI. 


Views  of  the  first  two  dissections  of  the  sole  of  the  foot  are  repre- 
sented in  the  Figures  of  this  Plate. 

Figure  I. 

In  this  Illustration  the  dissection  of  the  first  layer  of  muscles  with  the 
superficial  vessels  and  nerves  is  displayed. 


PLATE  LV! 


o 


FIEST   LAYER   OF   MUSCLES. 


185 


After  the  removal  of  the  skin,  the  cutaneous  vessels  and  nerves  are 
to  be  souglit;  and  when  the  fat  and  the  subjacent  plantar  fascia  have 
been  taken  away,  the  first  layer  of  muscles  comes  into  sight.  The 
digital  nerves  and  vessels,  appearing  between  the  muscles  about  the  mid- 
dle (in  length)  of  the  foot,  are  next  to  be  traced  onwards  to  the  toes. 

FIRST  LAYER  OF  MUSCLES. 

Three  muscles  enter  into  this  layer: — the  central  one  is  the  short 
flexor  of  the  toes;  the  muscle  in  a  line  with  the  great  toe  is  the  abductor 
pollicis;  and  that  lying  along  the  outer  border  of  th3footis  the  abductor 
minimi  dis;iti. 


A.  Abductor  pollicis. 

B.  Flexor  brevis  digitorum. 

C.  Abductor  minimi  digiti. 

E.   Flexor  tendon  of  the  great  toe. 
H.  Lumbricales. 


K.  Transverse  ligament  of  the  toes. 

N.  Flexor  brevis  pollicis. 

O.  Flexor  minimi  digiti. 

P.  Interossei  of  the  outer  space. 


The  flexor  brevis  digitorum,  B,  acts  on  the  four  outer  toes;  and  it  is 
called  flexor  perforatus  from  its  tendons  being  pierced  by  those  of  the 
long  flexor.  The  muscle  has  a  narrow  origin  posteriorly  from  the  inner 
side  of  the  large  tubercle  at  the  back  of  the  os  calcis,  and  from  the 
investing  plantar  fascia.  About  the  middle  of  the  foot  it  is  divided  into 
four  fleshy  parts,  the  outer  being  very  small;  and  from  each  part  pro- 
ceeds a  tendon  -to  the  root  of  the  toe,  where  it  enters  a  fibrous  sheath 
with  a  slip  of  the  long  flexor  (Fig.  ii.).  Lastly,  in  the  sheath  the  tendon 
of  the  short  flexor,  I  (Fig.  ii.),  is  pierced  opposite  the  metatarsal  pha- 
lanx, as  in  the  finger,  for  the  passage  of  the  tendon  of  the  other  muscle, 
J;  and  it  is  then  inserted  by  two  parts  into  the  sides  of  the  middle 
phalanx. 

The  muscle  is  incased  in  a  sheath  of  the  plantar  fascia,  of  which  a 
piece  has  been  shown  on  the  surface.  Along  the  outer  side  lies  the  ab- 
ductor of  the  little  toe,  and  along  the  inner,  the  abductor  of  the  great 
toe.  The  parts  covered  by  it  are  delineated  in  Fig.  ii.,  viz.  the  tendons 
of  the  long  flexors  with  the  accessory  muscles,  and  the  plantar  vessels  and 
nerves.  Its  tendons  decrease  in  size  from  the  inner  to  the  outer  side; 
and  that  to  the  little  toe  may  be  very  small  and  not  pierced,  or  it  may  be 
even  absent:  near  the  toes  they  ara  crossed  by  the  digital  nerves. 


186  ILLDSTRATIONS   OF   DISSECTIONS. 

When  this  flexor  contracts  it  will  move  the  middle  phalanges  of  the 
four  outer  toes  towards  the  sole,  bending  the  first  phalangeal  joint,  as  in 
the  fingers. 

The  abductor  pollicis,  A,  the  most  internal  muscle  of  the  first  layer, 
takes  origin  behind  by  a  wide  attachment  to  the  inner  part  of  the  larger 
tubercle  of  the  os  calcis;  to  the  lower  border  of  the  internal  annular  liga- 
ment; to  the  inner  side  of  the  tarsus  (its  ligamentous  structures)  as  far 
forwards  as  the  scaphoid  bone;  and  to  the  plantar  fascia,  though  not  so 
largely  as  the  other  two  muscles.  Anteriorly  it  ends  in  a  tendon,  and  is 
inserted  into  the  inner  side  of  the  bace  of  the  metatarsal  phalanx  of  the 
great  toe,,  in  union  with  the  inner  head  of  the  short  flexor. 

Contained  in  a  sheath  of  the  plantar  fascia,  it  is  separated  behind 
from  the  short  flexor  of  the  toes  by  an  intermuscular  partition,  and  in 
front  by  the  internal  plantar  vessels  and  nerve  which  issue  between  the 
two.  In  Fig.  ii.  the  parts  covered  by  it  may  be  perceived,  viz.  the  long 
flexor  tendons,  the  accessory  muscle,  and  the  internal  plantar  vessels  and 
nerve. 

As  the  name  expresses  the  muscle  will  abduct  slightly  the  great  toe 
from  the  others;  but  as  it  lies  almost  parallel  with  the  digit  moved,  it  will 
be  employed  mainly  in  assisting  the  short  flexor  to  bend  the  metatarso- 
phalangeal joint. 

The  abductor  minimi  digiti,  C,  is  wide  behind,  like  the  abductor  pol- 
licis, and  arises  more  largely  from  the  os  calcis,  viz.  from  the  fore  part  of 
the  inner  or  larger  tubercle,  and  from  the  outer  tubercle;  and  many  fibres 
are  attached  to  the  plantar  fascia  both  superficially  and  on  the  outer  side. 
In  front  the  muscle  is  inserted  by  tendon  into  the  outer  side  of  the  meta- 
tarsal phalanx  of  the  little  toe. 

Like  the  two  preceding  muscles  it  is  invested  by  the  fascia.  Internal 
to  it  behind  is  the  short  flexor  of  the  toes,  with  an  intermuscular  septum 
of  fascia  intervening;  and  about  the  middle  of  the  foot  the  offsets  of 
the  plantar  vessels  and  nerves  separate  them.  When  the  muscle  is  everted, 
as  in  Fig.  ii.,  it  will  be  seen  to  rest  on  the  flexor  accessorius,  F,  the  peroneus 
longus,  and  the  short  flexor  of  the  little  toe,  0. 

The  muscle  can  abduct  the  little  toe  from  its  fellows,  and  bend  the  , 
first  joint  of  that  toe  after  the  same  manner  as  the  abductor  pollicis. 

Superficial  transverse  ligament  of  the  toes,  K.  In  the  form  of  a  flat- 
tened band  it  reaches  from  the  outer  to  the  inner  toe,  and  consists  of 
transverse  fibres  which  are  united  to  the  sheaths  of  the  flexor  tendons. 


SUPERFICIAL    AND    PLANTAR    ARTERIES. 


187 


Under  it  pass  the  digital  vessels  and  nerves.  It  serves  the  purpose  of 
uniting  together  the  roots  of  the  digits,  as  in  the  hand.  A  deeper  trans- 
verse ligament  connects  the  heads  of  the  metatarsal  bones. 


SUPERFICIAL  ARTERIES   OF  THE   SOLE. 

Kear  the  roots  of  the  toes  appear  the  digital  arteries,  which  spring 
from  the  plantar  trunks;  and  over  the  muscles  ramify  cutaneous  vessels 
of  the  posterior  tibial  and  plantar  arteries. 


a.  Cutaneous  branch  of  the  sole. 
h.  Internal  plantar  trunk. 

c.  External  plantar  trunk. 

d.  Digital  branch  of  outside  of  little 

toe. 

e.  Digital  branch  of  inside  of  great 

toe. 


/.  Digital  branch  of  first  and  second 

toes. 
g.  Digital  branch  of  second  and  third 

toes. 
li.  Digital  branch  of  third  and  fourth 

toes. 
i.   Digital  branch  of  fourth  and  fifth 

toes. 


Cutaneous  arteries.  The  teguments  of  the  posterior  part  of  the  sole 
receive  branches  from  the  posterior  tibial  trunk,  and  those  of  the  rest  of 
the  foot  are  supplied  by  the  plantar  arteries. 

The  cutaneous  i^lantar  of  the  posterior  tibial,  a,  is  shown  at  its  origin 
in  Plate  lv:  when  it  is  small  there  may  be  two  instead  of  one.  Piercing 
the  internal  annular  ligament  as  one  or  two  branches,  which  accompany 
the  cutaneous  nerve,,  it  ramifies  in  the  teguments  of  the  under  and 
fore  part  of  the  heel.     Its  vense  comites  join  the  posterior  tibial  veins. 

Cutaneous  branches  of  the  plantar  arteries  issue  by  the  sides  of  the 
flexor  brevis  digitoru'm — between  it  and  the  abductor  pollicis  internally, 
and  between  it  and  the  abductor  minimi  digiti  externally;  and  towards 
the  toes  the  cutaneous  offsets  are  furnished  by  the  digital  arteries: — 
These  several  branches  supply  the  integuments  anterior  to  the  distribu- 
tion of  the  artery,  a. 

T\\Q  plantar  arteries,  the  chief  vessels  of  the  sole  of  the  foot,  are  two 
in  number,  inner  and  outer;  they  are  derived  from  the  splitting  of  the 
posterior  tibial  at  the  lower  border  of  the  internal  annular  ligament;  and 
their  connection  with  muscles  at  the  hinder  part  of  the  foot  can  be 
observed  in  Fig.  ii. 

The  internal  plantar,  h,  is  directed  beneath  the  abductor  pollicis  (the 


188  ILLUSTRATIONS    OF    DISSECTIONS. 

sole  of  the  foot  being  up)  to  the  interval  between  this  muscle  and  the 
flexor  brevis  digitorum,  where  it  becomes  superficial  opposite  the  back 
of  the  first  interosseous  space.  It  is  then  directed  forwards  and  out  over 
the  flexor  tendons,  in  company  with  \ense  comites  and  the  internal  plan- 
tar nerye,  and  ends  at  the  fore  part  of  the  third  interosseous  space  by 
joining  the  third  digital  artery,  h. 

Whilst  the  artery  retains  its  deep  position  it  furnishes  cutaneous 
branches  of  the  sole,  muscular  branches  to  the  abductor  poUicis  and  flexor 
l^erforatus,  and  deep  offsets  to  the  bones  and  ligaments  of  the  inner 
part  of  the  tarsus.  After  the  vessel  reaches  the  surface  it  supplies  the 
following  superficial  digital,  and  deep  or  muscular  branches. 

The  superficial  digital  Iranches  are  three  slender  arteries  which  run 
forward,  and  are  thus  arranged: — 

The  most  internal  belongs  to  the  inner  side  of  the  foot  and  great  toe, 
and  gives  offsets  to  the  abductor  and  flexor  brevis  pollicis;  it  commu- 
nicates with  the  artery,  /,  of  the  first  interosseous  space  by  a  cross  branch 
under  the  long  flexor  tendon. 

The  second,  lying  over  the  first  interosseous  space,  joins  the  digital 
artery,  (j,  at  the  root  of  the  toes. 

The  third  enters  the  digital  artery,  A,  like  the  others.  * 

The  muscular  Iranclies,  which  are  shown  in  Fig.  ii.,  penetrate  the 
fibres  of  the  flexor  brevis  j)ollicis,  and  the  inner  two  lumbricales  muscles. 

The  external  ijlantar  artery,  c  (Fig.  ii.),  has  an  arched  course  to  the 
back  of  the  fourth  interosseous  space,  and  there  sinks  under  the  third 
layer  of  muscles  to  form  the  plantar  arch  (Plate  LVii.).  Covered  at  first 
by  the  abductor  pollicis,  it  is  placed  next  between  the  flexor  digitorum 
and  the  accessorius,  F,  and  finally  it  lies  in  the  interval  between  the 
flexor  of  the  toes  and  the  abductor  of  the  little  toe.  Vense  comites  are 
continued  on  the  sides  of  the  artery;  and  the  external  plantar  nerve  has 
the  same  course  and  connections. 

Collateral  branches  are  furnished  from  this  part  of  the  artery  to  the 
contiguous   muscles, — abductor   minimi,    flexor   digitorum,    and    flexor 


*  The  condition  of  the  arteiy  which  is  represented  in  this  Plate  differs  much 
from  that  which  is  ordinarily  described.  Tliis  arrangement  is  the  common  one; 
but  the  arteries  of  the  foot,  like  those  of  the  hand,  are  subject  to  variations,  and 
the  distribution  of  the  digital  branches  will  deviate  occasionally  from  that  above 
given. 


■INTERNAL    PLANTAR    NERVE. 


189 


accessorius;  and  to  the  bones  and  ligaments  of  the  outer  side  of  the  foot: 
these  last  communicate  with  the  arteries  on  the  dorsum. 

From  the  deep  part  of  the  plantar  artery  (plantar  arch)  the  digital 
arteries  on  the  sides  of  the  toes  are  derived;  but  a  more  complete  view  of 
these  will  be  obtained  in  the  following  Plate. 


NERVES   OF  THE  SOLE. 

The  nerves,  like  the  arteries,  consist  of  cutaneous  and  deep  branches; 
the  former  come  from  the  j)osterior  tibial  and  plantar  nerves;  and  the 
latter  are  the  terminal  pieces  of  the  posterior  tibial  nerve. 


1.  Cutaneous  plantai-  nerve. 

2.  Internal  plantar  trunk. 

3.  External  plantar  trunk. 

4.  Digital  of  inner  side  of  great  toe. 

5.  Digital  of  first  and  second  toes. 


6.  Digital  of  second  and  third  toes. 

7.  Digital  of  third  and  fourth  toes. 

8.  Communicating  of  plantars. 

9.  Digital  of  fourth  and  fifth  toes. 
10.  Digital  of  outside  of  little  toe. 


The  cutaneous  plantar  nerve,  1,  whose  origin  appears  in  the  preced- 
ing Plate,  ramifies  in  the  integuments  of  the  heel,  viz.,  in  that  part  on 
which  the  foot  rests  in  standing. 

Along  the  sides  of  the  flexor  brevis  digitorum  other  nerves,  derived 
from  the  plantar  trunks,  pierce  the  fascia,  and  becorhe  cutaneous.  Near 
the  roots  of  the  toes,  and  along  the  borders  of  the  foot,  branches  are 
also  furnished  to  the  teguments  from  the  digital  nerves. 

The  2}lantar  nerves,  two  in  number  like  the  arteries,  are  obtained 
from  the  bifurcation  of  the  posterior  tibial  trunk  beneath  the  annular 
ligament  (p.  183).  In  Fig.  ii.  the  first  or  deep  part  of  each  is  visible; 
and  their  termination  on  the  toes  may  be  observed  in  Fig.  i. 

The  internal  nerve  supplies  but  few  muscles,  and  ends  anteriorly  in 
digital  branches  for  the  three  inner  toes  and  half  the  fourth.  Begin- 
ning on  the  inner  side  of  the  heel,  it  is  directed  forwards  under  cover 
of  the  abducftor  poUicis  to  the  middle  (in  length)  of  the  sole.  Here  the 
nerve  becomes  superficial  between  the  abductor  and  the  flexor  digitorum, 
and  is  inclined  forwards  and  outwards  towards  the  fore  part  of  the  third 
interosseous  space  where  it  ends  in  the  fourth  digital  nerve,  7.  In  the 
superficial  part  of  its  course  it  lies  over  the  flexor  tendons,  being  covered 
by  the  plantar  fascia. 

While  the  nerve  is  beneath  the  abductor  pollicis  it  gives  branches  to 


190  ILLUSTRATIONS    OF    DISSECTIONS. 

tliat  muscle  and  the  flexor  digitorum;  and  after  it  becomes  superficial  it 
furnishes  the  digital  branches. 

Tlie  digital  hranclies,  four  in  number,  are  named  first,  second,  and  so 
forth,  from  the  inner  to  the  outer  border  of  the  foot.  At  first  they  are 
covered  by  the  plantar  fascia,  but  near  the  root  of  the  toes  they  issue 
between  the  processes  of  that  fascia,  though  the  first  or  most  internal 
enters  the  teguments  farther  back  than  the  rest.  Each,  except  the  first, 
bifurcates  to  supply  the  contiguous  sides  of  two  toes.  On  the  digits 
they  are  continued  along  the  lateral  aspect,  as  in  the  hand;  and  distrib- 
uting in  their  course  cutaneous  and  articular  offsets,  end  on  the  last 
phalanx  in  a  tuft  of  fine  nerves  from  which  the  ball  of  the  digit  is  prin- 
cipally supplied. 

The  first  digital  nerve,  4,  courses  to  the  inner  side  of  the  great  toe, 
and  sends  many  cutaneous  branches  to  the  inside  of  the  foot  anterior  to 
the  tarsus:  an  offset  from  it  enters  the  flexor  brevis  pollicis. 

The  second  digital,  5,  supplies  the  most  internal  lumbricalis  muscle, 
and  ends  on  the  sides  of  the  second  and  third  toes. 

The  third  digital,  6,  belongs  to  the  neighboring  sides  of  the  third 
and  fourth  toes,  and  gives  a  branch  to  the  second  lumbricalis  muscle. 

The  fourth  digital,  7,  is  distributed,  like  the  others,  to  the  collateral 
sides  of  the  third  and  fourth  toes,  and  is  joined  by  a  communicating 
branch,  8,  from  the  external  plantar. 

The  internal  plantar  nerve  in  the  foot  resembles  the  median  in  the 

hand  in  its  supply  to  three  digits  and  a  half;  in  the  arrangement  of  its 

digital  branches;  and  in  having  a  communication  with  the  nerve  fur- 

.   .  .         ♦  ... 

nished  to  the  remainmg  digits.     Like  the  median  it  gives  branches  also 

to  the  first  two  lumbricales,  and  the  abductor  and  flexor  brevis  pollicis. 

But  as  the  muscles  of  the  first  digit  are  not  alike  in  the  hand  and 
foot  the  distribution  of  the  two  nerves  is  not  identical  throughout. 
For  instance  in  the  foot  there  is  not  any  branch  corresponding  with  that 
given  by  the  median  to  the  opponens  pollicis;  and  none  in  the  hand 
answering  to  the  nerve  of  the  flexor  perforatus  in  the  foot.  Lastly,  the 
whole  of  the  flexor  brevis  pollicis  is  supplied  by  the  internal  plantar 
nerve  in  the  foot,  but  only  the  outer  head  of  the  muscle  in  the  hand 
receives  a  branch  from  the  median. 

The  external  plantar  nerve,  3,  is  chiefly  expended  in  muscles.,  and 
emits  digital  branches  only  to  one  toe  and  a  half,  like  the  ulnar  nerve  in 
the  hand. 


■  SECOND    LAYER    OF    MU80LE8.  191 

It  begins  inside  the  heel  witli  the  internal  plantar  (Fig.  ii.),  and  u 
directed  outwards  across  the  foot  towards  the  back  of  the  fourth  interos- 
seous space,  where  it  sends  off  digital  branches,  and  then  sinks  into  the 
sole  of  the  foot  witli  the  external  plantar  artery  to  end  in  deep  muscles: 
its  termination  may  be  ascertained  in  Plate  LVii.  In  this  course  the 
nerve  lies  at  first  under  the  abductor  pollicis,  nextly  between  the  flexor 
brevis  digitorum  and  flexor  accessorius,  and  lastly  in  the  intermuscular 
space  between  the  flexor  of  the  digits  and  the  abductor  mmimi  digiti.  It 
is  accompanied  by  the  external  plantar  artery  and  venae  comites,  but  th© 
nerve  is  not  always  situate  on  the  same  side. 

From  this  part  of  the  nerve  branches  are  sent  to  the  abductor  of  the 
little  toe,  and  the  flexor  accessorius:  these  are  visible  in  Fig.  ii. 

The  digital  branches,  two  in  number,  run  forwards  beneath  the  plan- 
tar fascia,  and  become  subcutaneous  near  the  toes,  between  the  digital 
processes  of  that  fascia:  but  the  most  external  nerve  pierces  the  fascia 
farther  back  than  the  other.  One  of  the  two  (internal)  splits  at  the 
front  of  the  fourth  interosseous  space,  like  the  branches  of  the  other 
plantar  nerve,  to  end  in  the  adjacent  borders  of  the  fourth  and  fifth  toes; 
but  the  other  remains  undivided  on  the  outer  side  of  the  little  toe.  As 
these  branches  are  continued  along  the  toes  they  have  the  same  arrange- 
ment as  the  digital  branches  of  the  internal  plantar  nerve. 

The  branch  for  the  outer  side  of  the  little  toe,  10,  gives  many  cutane- 
ous offsets  to  the  anterior  half  of  the  outer  border  of  the  foot:  it  may 
supply  also  the  contiguous  muscles,  viz.,  the  flexor  minimi  digiti,  0,  and 
the  interossei  of  the  fourth  space. 

The  branch,  9,  which  ramifies  in  the  collateral  sides  of  the  fiith  and 
fourth  toes,  communicates  by  means  of  the  branch,  8,  with  the  internal 
plantar,  but  does  not  supply  any  muscle. 

FiGUEE  II. 

The  second  layer  of  muscles  of  the  foot,  and  the  trunks  of  the  plantar 
vessels  and  nerves  may  be  studied  with  this  Figure. 

To  obtain  this  view  the  first  layer  of  muscles  is  to  be  cut  through 
near  the  heel,  and  is  to  be  removed  in  part,  as  is  here  shown.  Then 
the  dissection  will  be  completed  after  the  removal  of  the  fat  and  fascia. 


192 


ILLUSTKATIONS    OF    DISSECTIONS. 


SECOND  LAYER  OF  MUSCLES. 


In  this  group  are  included  the  flexors  of  the  digits  which  take  origin 
at  the  back  of  the  leg,  viz.,  flexor  longus  pollicis,  and  flexor  longus  digi- 
torum  with  its  accessory  muscles.  The  same  letters  in  the  two  Figures 
mark  the  same  parts. 


D.  Flexor  longus  digitorum. 

E.  Flexor  longus  pollicis. 

F.  Flexor  accessorius. 

G.  Inner  head  of  accessorius. 
H.  Lumbricales. 

I.  Tendon  of  flexor  brevis  digito- 


J.    Tendon  of  flexor  longus  digito- 
rum. 
L.  Sheath  of  flexor  tendons. 
N,  Flexor  brevis  pollicis. 
O.  Flexor  minimi  digiti. 
P.  Interossei. 
Q.  Tendon  of  peroneus  longus. 


Tendon  of  fiexor  longus  jiollicis,  E.  Issuing  at  the  back  of  the  foot 
from  a  groove  in  the  astragalus  and  os  calcis,  where  it  is  enveloped  by  a 
synovial  membrane,  it  is  directed  inwards  to  the  root  of  the  great  toe;  it 
then  enters  the  digital  sheath,  where  it  is  incased  in  a  second  synovial  sac, 
and  is  inserted  into  the  base  of  the  ungual  phalanx. 

In  the  foot  it  rests  on  the  flexor  brevis  pollicis,  N,  and  lies  under  the 
tendon  of  the  flexor  longus  digitorum,  D:  to  this  last  tendon  it  is  con- 
nected by  a  slip,  which  is  prolonged  most  commonly  into  those  pieces  of 
the  common  fiexor  of  the  digits  belonging  to  the  second  and  third  toes, 
and  in  greatest  proportion  to  the  inner  one  (Turner).* 

Tendon  of  flexor  longus  digitorum,  D.  This  tendon  appears  on  the 
inner  part  of  the  foot;  it  is  then  inclined  towards  the  middle  of  the  sole, 
and  divides  into  four  pieces  for  the  four  outer  toes.  Each  of  these  pieces, 
J,  enters  the  digital  sheath  with  a  tendon,  I,  of  the  short  flexor,  and 
having  pierced  that  tendon  is  inserted  into  the  base  of  the  last  phalanx. 

As  the  tendon  escapes  from  the  internal  annular  ligament  it  lies  inter- 
nal to  the  flexor  pollicis,  and  is  surrounded  by  a  synovial  membrane  as 
far  as  the  place  of  junction  with  it  of  the  accessorius  muscle,  F;  and  as 
it  crosses  over  the  tendon  of  the  flexor  of  the  great  toe  a  communication 


*  On  Variability  in  Human  Structure,  by  William  Turner,  M.B.;  Trans,  of 
Royal  Soc.  of  Edinb.,  vol.  xxiv. 


.SECOND    LAYER    OF    MUSCLES.  193 

is  established  between  the  two,  as  before  said.  Finally  from  the  pieces 
into  which  the  tendon  splits  a  group  of  four  accessory  muscles — the 
lumbricales — takes  origin.  The  parts  covered  by  the  tendon  are  set  forth 
in  Fig.  i.  of  the  following  Plate. 

Sheaths  of  the  flexor  tendons.  Along  the  four  outer  toes  the  pieces  of 
the  short  and  long  flexor  are  lodged  in  a  partly  osseous  and  partly  mem- 
branous canal,  as  in  the  fingers.  Towards  the  plantar  surface  the  sheath 
is  formed  by  fibrous  bands,  L,  which  are  strongest  opposite  the  centre  of 
the  two  nearest  phalanges,  and  thinnest  opposite  the  joints;  whilst  at  the 
opposite  aspect  it  is  constructed  by  the  bones  which  are  hollowed  out  to 
be  adapted  to  the  tendons.  A  synovial  membrane  lubricates  the  sheath, 
as  in  the  fingers,  and  reaches  posteriorly  along  <-he  tendons  nearly  to  the 
attachment  of  the  lumbricales.  In  the  sheath  accessory  bands  are  con- 
nected with  the  tendons;  and  these  are  similar  to,  but  not  so  well  marked 
as  those  in  the  hand  (vol.  i.,  p.  80).  In  the  sheath  of  th3  great  toe  only 
one  tendon  is  contained. 

Action  of  the  flexors  on  the  toes.  In  both  members  the  bending  of  the 
digits  takes  place  in  the  same  order.  Firstly  the  hinder  phalangeal  joint 
is  flexed  by  the  short  flexor  carrying  down  the  middle  phalanx.  Nextly 
the  anterior  joint  is  bent  by  the  long  flexor  drawing  the  last  phalanx 
towards  the  sole.  And  lastly  the  metatarso-jDhalangeal  joint  ^'s  flexed  by 
the  indirect  action  of  the  two  tendons  bound  to  the  first  phalanx  by  the 
sheath  of  the  digit,  and  by  the  direct  Contraction  of  the  lumbricalis  and 
interossei  muscles. 

The  musculus  accessorius,  F,  is  a  squarish  fleshy  mass,  which  has 
received  its  name  from  assisting  the  long  flexor  to  bend  the  digits.  It  is 
bifurcated  behind,  and  arises  externally  by  tendon  from  the  outer  surface 
of  the  OS  calcis  and  the  long  plantar  ligament,  and  internally  by  a  thick 
fleshy  part,  G,  from  the  inner  concave  surface  of  that  bone.  About  the 
middle  of  the  sole  it  becomes  tendinous,  and  ends  most  commonly  by 
joining  the  flexor  perforans  and  the  slip  of  the  flexor  pollicis,  so  as  to 
assist  in  forming  the  tendons  for  the  second,  third,  and  fourth  digits.* 

On  the  muscle  rest  the  external  plantar  nerve  and  vessels,  and  the 
flexor  perforatus;  and  under  it  lie  the  os  calcis  and  the  long  plantar  liga- 
ment. Between  the  heads  of  origin  of  the  muscle  a  piece  of  the  plantar 
ligament  appears. 


*  Professor  Turner  in  the  Paper  (Trans,  of  the  Roy.  See.  of  Edinb.)  before 
referred  to, 

13 


194:  ILLUSTRATIONS    OF    DISSECTIONS. 

Supposing  the  long  flexor  to  act  alone  the  four  outer  toes  would  be 
bent  somewhat  under  each  other;  but  when  the  accessorius  contracts  it 
opposes  that  oblique  inward  movement  of  the  digits,  and  with  the  help  of 
the  flexor  ^oerforatus  bends  the  toes  directly  back. 

Lumljricales,  H.  Four  in  number,  they  serve  as  accessory  flexor 
muscles  to  the  four  outer  toes;  and  are  named,  first,  second,  etc.,  from 
the  inner  to  the  outer  side  of  the  foot.  They  take  origin  behind  from  the 
pieces  into  which  the  flexor  perforans  splits,  the  most  internal  being 
fixed  commonly  to  only  one,  and  each  of  the  others  to  two  tendinous 
slips.  Near  the  metatarso-phalangeal  articulation  each  ends  in  a  tendon, 
which  passes  at  the  tibial  side  of  the  toe  to  join  the  extensor  tendon  on 
the  dorsum  of  the  first  phalanx:  as  they  bend  down  by  the  sides  of  the 
joints  they  are  closely  attached  to  the  metatarsal  phalanx,  or  are  con- 
nected with  it  by  a  thin  tendinous  slip. 

The  muscles  decrease  in  size  from  the  first  to  the  fourth.  At  the  root 
of  the  toes  they  become  cutaneous  between  the  processes  of  the  plantar 
fascia,  with  the  digital  nerves  and  arteries,  and  they  appear  there  even 
before  the  removal  of  the  superficial  flexor  muscle  (Fig.  i.). 

Contracting  with  the  long  flexor  these  muscles  bring  towards  the  sole 
the  metatarsal  phalanges,  thus  serving  as  flexors  of  the  metatarso-phalan- 
geal joints  of  the  four  outer  toes. 

Plantar  arteries.  In  the  second  Figure  the  course  of  these  vessels 
between  the  first  two  strata  of  muscles  may  be  observed.  Of  the  two  the 
external  is  the  largest,  and  furnishes  most  digital  branches  to  the  toes; 
but  a  more  complete  view  of  these  arteries  will  be  contained  in  the  next 
Plate.  In  this  Figure  the  small  muscular  branches  of  the  internal  plan- 
tar artery  to  the  inner  two  Inmbricales,  and  to  part  of  the  flexor  brevis 
pollicis  are  displayed. 

Plantar  nerves.  Two  in  number  like  the  arteries,  there  is  not  the 
same  disparity  in  size  between  them,  for  though  one  supplies  most  digits, 
the  other  gives  most  offsets  to  muscles.  They  are  placed  with  the  blood- 
vessels between  the  first  two  muscular  strata.  The  distribution  of  the 
internal  nerve  to  three  digits  and  a  half  and  a  few  muscles  has  been  given 
at  p.  189;  and  the  arrangement  of  the  external  nerve,  which  is  furnished 
to  one  digit  and  a  half  and  many  muscles,  will  be  afterwards  considered. 


PLATE  LVII 


___  ,.,j«(ae««rei'^*^^^  '^^y*'^^ 


CD 


O 


MUSCLES    OF    THE    THIRD    LAYER. 


195 


DESCRIPTION  OF  PLATE  LVII. 


I]sr  this  Plate  the  last  two  stages  of  the  dissection  of  the  foot  are 
delineated. 

FiGUEE  I. 

Part  of  the  external  plantar  vessels  and  nerve,  with  their  branches, 
and  the  short  muscles  of  the  great  and  the  little  toe  are  represented  in 
this  Figure. 

After  making  the  preparation  of  the  parts  illustrated  in  Figure  ii.  of 
the  foregoing  Plate,  the  dissection  of  the  third  stage  will  be  completed 
by  dividing  the  accessorius  muscle  and  the  tendons  of  the  flexors  of  the 
digits  about  two  inches  in  front  of  the  heel;  and  by  removing  the  areolar 
tissue  from  the  muscles,  vessels,  and  nerves,  after  the  flexor  perforans 
with  its  lumbricales  has  been  thrown  forwards  to  the  toes.  Whilst  the 
flexor  tendon  is  being  raised,  the  small  nerves  and  arteries  to  the  outer 
two  lumbricales  muscles  are  to  be  sought  with  care. 


MUSCLES  OF  THE  THIRD  LAYER. 

This  stratum  consists  chiefly  of  the  short  muscles  of  the  first  and 
fifth  digits,  which  reach  scarcely  farther  back  than  the  metatarsal  bones: 
they  are  the  short  flexor  and  adductor  of  the  great  toe,  the  short  flexor  of 
the  little  toe,  and  a  fourth  muscle  (trans versalis  pedis)  which  crosses  the 
heads  of  the  metatarsal  bones. 


N.  Flexor  brevis  pollicis. 
O.  Flexor  brevis  minimi  digiti. 
Q.  Peroneus  longus. 
R.  Adductor  pollicis. 


S.  Trans  versalis  pedis. 

T.  Part  of  the  tendon  of  the  tibialis 

posticus. 
U.  Long  plantar  ligament. 


The  -flexor  hrevis  pollicis,  N,  the  most  internal  muscle  of  the  set,  is 
pointed  and  tendinous  behind,  but  is  split  anteriorly  into  two  pieces  or 
heads.     Its  tendon  is  attached  posteriorly  to  the  cuboid  bone,  and  blends 


196  ILLUSTRATIONS    OF   DISSECTIONS. 

with  the  prolongation,  T,  from  the  tendon  of  the  tibialis  posticus  to  the 
outer  cuneiform  bone.  Towards  the  front  of  the  metatarsal  bone  it  is 
divided  into  two  heads,  and  these  are  inserted  into  the  base  of  the  first 
phalanx, — the  inner  joining  the  abductor  pollicis,  A,  and  the  outer 
blending  with  the  adductor,  R. 

Superficial  to  the  muscle  is  the  tendon  of  the  long  flexor;  and  under- 
neath it  lie  the  deep  vessels  of  the  foot.  In  each  head  of  insertion  a 
sesamoid  bone  is  contained. 

The  muscle  draws  towards  the  sole  the  metatarsal  phalanx,  to  which 
the  long  flexor  tendon  is  not  attached,  and  thus  bends  the  metatarso- 
phalangeal joint  of  the  great  toe. 

The  adductor  pollicis,  R,  arises  behind  from  the  sheath  of  the  pero- 
neus  longus  tendon,  Q,  and  from  the  bases  of  the  second,  third,  and 
fourth  metatarsal  bones.  In  front  it  joins  the  outer  head  of  the  flexor 
brevis  pollicis,  and  is  inserted  into  the  outer  side  of  the  first  phalanx  of 
the  gi'eat  toe. 

It  is  concealed  by  the  flexor  perforans  and  the  lumbricales;  it  covers 
some  of  the  interossei,  and  the  external  plantar  vessels  and  nerve.  United 
with  it  at  the  insertion  is  the  trans versalis  pedis. 

Acting  with  the  transversalis  pedis  the  muscle  will  adduct  the  great 
toe  to  the  others;  and  in  concert  with  the  short  flexor  and  abductor  it  will 
bend  the  metatarso-phalangeal  joint. 

Transversalis  pedis,  S.  This  is  a  thin  fleshy  slip,  which  lies  across 
the  heads  of  the  metatarsal  bones.  It  arises  by  bundles  of  fibres  from  the 
capsule  of  the  metatarso-phalangeal  articulations  of  the  fourth,  third,  and 
second  toes  (sometimes  the  fifth);  and  from  the  fascia  covering  the  inter- 
ossei muscles.  Internally  it  is  inserted  with  the  adductor  into  the  nearest 
phalanx  of  the  great  toe. 

By  its  cutaneous  surface  it  is  in  contact  with  the  flexor  perforans,  the 
lumbricales,  and  the  digital  nerves;  and  by  the  deep,  it  touches  t]ie  inter- 
ossei and  the  digital  vessels.  The  muscle  is  described  by  Theile  as  a 
short  head  of  the  adductor  pollicis. 

From  its  position  and  attachment  to  the  four  inner  toes  it  will  approx- 
imate them  to  one  another. 

HhQ  flexor  brevis  minimi  digiti,  0,  lies  on  the  metatarsal  bone  of  the 
little  toe,  and  resembles  the  interossei.  Posteriorly  it  arises  from  the 
base  of  the  fifth  metatarsal  bone,  and  from  the  sheath  of  the  peroneous 
longus  tendon;  and  it  is  inserted  anteriorly  into  the  base  of  the  first  pha- 


EXTERNAL  PLANTAR  NERVE. 


197 


lanx  after  blending  with  the  capsule  of  the  metatarso-phalangeal  articu- 
lation, and  into  the  fore  part  of  the  metatarsal  bone  (Tlieile). 

As  the  name  signifies  t;he  muscle  may  be  used  as  a  flexor  of  the  meta- 
tarso-phalangeal joint;  but  it  may  draw  down  slightly  the  outer  border  of 
the  foot  in  consequence  of  its  attachment  to  the  metatarsal  bone. 


EXTERNAL  PLANTAR  NERVE. 

As  far  as  the  root  of  the  little  toe  the  external  plantar  with  its  digital 
offsets  was  shown  in  the  preceding  Plate,  and  the  remainder  or  the  deep 
part  of  the  nerve  is  represented  in  this  view. 


2.  Internal  plantar  nerve,  cut. 

3.  External  plantar  nerve. 

4.  Superficial  or  digital  part  of  ex- 

ternal plantar. 


5.  Deep  part  of  external  plantar. 

6.  Branch  to  transversalis  pedis. 

ft  Branches    to    outer   two  lumbri- 
cales. 


The  deeip  part  of  the  external  'plantar  nerve,  5,  is  directed  inwards 
beneath  the  flexor  perforans  and  the  lubricales,  and  ends  in  branches  for 
the  adductor  pollicis,  R.  In  this  course  it  accompanies  the  external  plan- 
tar artery,  and  distributes  offsets  to  the  neighboring  muscles  of  the  third 
and  fourth  strata,  which  are  referred  to  below: — 

To  the  under  surface  of  the  adductor  poUicis  two  cr  three  branches 
(the  terminal  pieces  of  the  nerve)  are  distributed;  one  is  shown  piercing 
the  outer  border. 

A  slender  branch,  6,  enters  the  transversalis  pedis:  in  this  foot  it  was 
divided  into  two. 

For  each  of  the  outer  two  lumbricaies  there  is  a  small  branch  or  nerve, 
f,  which  enters  the  under  surface  with  an  arterial  offset.  Commonly 
these  branches  are  destroyed  as  the  long  flexor  muscle  is  raised. 

All  the  interossei  receive  branches  from  the  external  plantar,  but  these 
are  more  fully  illustrated  in  Fig.  ii. 

In  its  distribution  in  the  foot  this  nerve  resembles  closely  the  ulnar 
nerve  in  the  hand.  Like  its  representative  in  the  other  member  it  gives 
many  muscular  and  but  few  digital  branches.  Thus  it  supplies  one  digit 
and  a  half,  and  the  teguments  of  that  border  of  the  foot  which  is  in  a 
line  with  the  smallest  digit.  Like  the  ulnar  too  it  furnishes  branches  to 
all  the  muscles  of  the  small  digit,  and  to  the  adductor  of  the  large  digit; 


198  ILLUSTRATIONS    OF   DISSECTIONS. 

and  in  the  same  way  as  that  nerve  it  sends  offsets  to  the  outer  two  lum- 
bricales  and  to  all  the  interossei. 

Differences  in  the  distribution  of  the  two  nerves  are  due  to  a  want  of 
similarity  in  the  muscles  of  the  first  and  fifth  digits,  and  to  the  existence 
of  some  special  muscles  in  each  member.  For  instance  the  ojsponens  or 
adductor  minimi  digiti  is  present  in  the  hand  but  not  in  the  foot,  and 
will  have  a  separate  branch  from  the  ulnar.  The  short  flexor  of  the 
thumb  is  a  less  simple  muscle  than  that  of  the  great  toe,  and  is  supplied 
in  j3art  (inner  head)  by  the  ulnar;  whilst  the  external  plantar  does  not 
reach  the  homologous  muscle  in  the  foot. 

One  special  muscle  in  the  hand  (palmaris  brevis)  is  supplied  by  the 
ulnar;  and  two  special  muscles  in  the  foot  (accessorius  and  trans versalis 
pedis)  obtain  their  nerves  from  the  external  plantar. 

The  external  plantar  artery,  c,  crosses  the  sole  of  the  foot  with  its 
nerve,  to  form  the  plantar  arch.  Digital  and  muscular  branches  arise 
from  the  arch:  the  former  of  these  and  the  trunk  will  be  delineated  in 
Fig.  ii. ;  and  the  latter,  which  enter  the  neighboring  muscles,  are  visible 
in  this  stage. 

Each  of  the  two  external  lumbricales  receives  an  arterial  twig;  and 
there  is  sometimes  another  branch  for  the  second  lumbricalis  muscle,  as 
in  this  dissection. 

The  transversalis  pedis  is  supplied  on  the  under  surface  by  one  or  more 
of  the  subjacent  digital  arteries. 

For  the  interossei  of  the  three  outer  spaces  offsets  are  derived  from 
the  digital  arteries  and  the  arch  (Fig,  ii. ). 

Branches  to  the  adductor  pollicis  penetrate  the  fibres  at  the  under 
surface,  like  the  nerves. 

From  the  most  external  digital  artery  proceed  branches  for  the  flexor 
brevis  minimi  digiti. 

Veins.  The  companion  veins  of  the  plantar  arch  and  its  branches 
were  purposely  removed  in  the  dissection,  to  render  the  Figure  less  com- 
plicated. 

Figure  II. 

The  fourth  stage  of  the  dissection  of  the  foot  is  depicted  in  this  Fig- 
ure. 

By  cutting  across  and  removing  the  adductor  and  part  of  the  flexor 


FOURTH    LAYER    OF    MUSCLES. 


199 


brevis  pollicis  the  plantar  arch  will  be  laid  bare;  and  by  removing  the 
transversalis  pedis  and  the  transverse  metatarsal  ligament  beneath  it,  and 
passing  the  scalpel  backwards  for  a  short  distance  in  the  centre  of  the 
three  outer  intermetatarsal  spaces  the  interossei  muscles  will  be  defined. 
On  the  removal  of  some  areolar  tissue  from  the  hinder  part  of  the  sole, 
the  insertion  of  the  tibialis  posticus,  the  tendon  of  the  peroneus  longus, 
some  ligaments  of  the  foot,  and  small  deep  anastomotic  vessels  come  into 
sight. 


MUSCLES  OF  THE  FOURTH  LAYER. 

In  the  last  layer  of  the  sole  of  the  foot  are  included  the  interossei,  and 
the  tendons  of  insertion  of  the  tibialis  posticus  and  peroneus  longus. 
When  the  same  letters  are  used  in  the  Figures  they  point  to  the  same 
parts. 


M. 
V. 

w. 

Y. 


1 


Prolongations  of  the  tendon 
of  the  tibialis  posticus  at  its 
insertion. 


X.  Three  plantar  interossei. 
Z.  Four  dorsal  interossei. 


The  interossei  muscles  are  seven  in  number,  and  fill  the  intervals  be- 
tween the  metatarsal  bones.  Two  are  lodged  in  each  intermetatarsal 
space,  except  in  the  inner  where  there  is  only  one;  and  they  are  attached 
to  the  bones  bounding  laterally  the  spaces:  they  are  arranged  into  a  plan- 
tar and  a  dorsal  set. 

The  plantar  set,  X,  three  in  number,  are  slender  fleshy  slips,  which 
lie  in  the  three  outer  spaces,  and  arise  each  from  a  single  metatarsal 
bone,  viz.,  fifth,  fourth,  and  third.  Opposite  the  metatarso-phalangeal 
joint  each  becomes  tendinous,  and  is  inserted  into  the  inner  side  of  the 
base  of  the  first  phalanx  of  its  toe;  a  slip  is  prolonged  from  it  to  join  the 
extensor  tendons  on  the  dorsum  of  the  phalanx. 

The  dorsal  set,  Z,  are  four  in  number,  one  being  placed  in  each  of  the 
intermetatarsal  spaces.  Each  has  a  double  origin  laterally  from  the  two 
metatarsal  bones  between  which  it  is  lodged.  Anteriorly  they  end  in 
tendons,  which  are  inserted,  like  the  plantar  muscles,  into  the  fibular 
side  of  the  fourth  and  third  toes,  and  into  both  sides  of  the  second  toe: 
they  join  also  the  extensor  tendons  on  the  dorsum. 

All  the  muscles  are  visible  in  the  sole  of  the  foot,  where  they  are 


200  ILLdSTEATIONS    OF    DISSECTIONS. 

covered  by  fascia,  by  the  external  plantar  nerve,  and  the  plantar  arch  and 
its  branches:  near  the  toes  the  transversalis  pedis  and  the  transverse  me- 
tatarsal ligament  lie  on  them.  On  the  dorsum  of  the  foot  only  the  dor- 
sal set  appear;  and  they  are  pierced  behind  by  arteries  passing  from  the 
one  aspect  of  the  foot  to  the  other. 

The  chief  office  of  these  muscles  is  to  approximate  the  four  outer  toes 
towards,  or  to  remove  them  from  the  great  toe;  and  they  act  therefore  as 
abductors  and  adductors  of  those  digits  to  the  inner  one.  For  instance 
the  three  plantar  and  the  innermost  dorsal  muscle  adduct  the  four  smaller 
to  the  larger  toe;  and  the  remaining  three  muscles  of  the  dorsal  set  will 
move  the  second,  third,  and  fourth  toes  away  from  that  digit,  so  as  to 
become  abductors. 

When  the  four  outer  toes  are  being  bent  by  the  action  of  the  flexors 
the  interossei  will  help  in  the  completion  of  the  movement;  and  when 
the  digits  have  been  extended  these  muscles  will  serve  to  fix  the  first  pha- 
langes against  the  metatarsal  bones. 

Tendon  of  the  peroneus  longus,  Q.  The  fleshy  belly  of  the  muscle  in 
the  leg  is  delineated  in  the  following  Plate;  and  only  part  of  the  course 
of  its  tendon,  and  the  insertion,  appear  in  this  Figure.  As  now  seen, 
the  tendon  winds  round  the  outer  surface -of  the  os  calcisto  cross  the  foot 
from  the  outer  to  the  inner  side.  At  first  it  is  received  into  a  groove  in 
the  cuboid  bone,  and  is  then  continued  forwards  to  be  inserted  into  the 
base  of  the  metatarsal  bone  of  the  great  toe,  and  into  the  fore  part  of  the 
internal  cuneiform  bone;  sometimes  also  by  a  slij)  into  the  base  of  the 
second  metatarsal  bone. 

As  the  tendon  crosses  the  sole  it  is  contained  in  a  sheath  which  is 
formed  towards  the  outer  part  by  the  long  plantar  ligament,  U,  and  the 
cuboid  bone,  and  at  the  inner  part  by  areolar  tissue;  and  its  motion  in 
the  sheath  is  facilitated  by  a  synovial  sac  which  extends  to  the  insertion. 
On  the  outer  aspect  of  the  cuboid  bone  the  tendon  becomes  flattened  and 
thickened,  and  at  that  spot  it  contains  either  fibro-cartilage  or  a  sesamoid 
bone. 

Insertion  of  the  tibialis  posticus,  T.  Arising  at  the  back  of  the  leg 
(Plate  LV. )  its  tendon  passes  along  the  inner  side  of  the  foot,  supporting 
the  articulation  between  the  astragalus  and  scaphoid  bone,  and  is  inserted 
into  the  tubercle  on  the  inner  and  under  part  of  the  os  scaphoides. 
From  the  insertion  processes  are  continued  to  several  of  the  tarsal  and 
metatarsal  bones: — one,  V,  reaches  the  internal  cuneiform;  another,  Y, 


PJ.ANTAR    ARCH    AND    BRANCHES. 


201 


is  attached  to  tlie  middle  cuneiform  and  the  second  metatarsal;  a  third, 
^y,  is  prolonged  to  the  external  cuneiform,  the  cuboid,  and  the  third  and 
fourth  metatarsal  bones;  and  a  fourth,  M,  is  reflected  backwards  to  be 
fixed  into  the  os  calcis.  In  short,  the  tendon  is  attached  to  all  the  tarsal 
bones  except  the  astragalus;  and  to  the  metatarsal  bones  with  the  excep- 
tion of  those  of  the  great  and  the  little  toe. 


DEEP  VESSELS  OF  THE  SOLE. 

Both  tibial  yessels  end  in  the  sole  of  the  foot — the  anterior  passing 
through  the  first  interosseous  space,  and  the  posterior  entering  at  the  in- 
ner side  of  the  heel;  and  both  furnish  digital  arteries  to  the  toes. 


c.  External  plantar  trunk. 

d.  Digital  branch  of  outside  of  little 

toe. 

e.  Digital  branch  of  inside  of  great 

toe. 
/.  Digital  branch  of  first  and  second 

toe. 
g.  Digital  branch  of  second  and  third 

toes. 


h.  Digital  branch  of  third  and  fourth 

toes. 
i.   Digital  branch  of  fourth  and  ftftk 

toes. 
I,   Dorsal  artery  of  the  foot. 
n.  Artery  of  the  great  toe. 
o.  ComrQunicating    branch   to  deep 

arch. 


The  plantar  arch  is  the  curved  terminal  part  of  the  external  plantar 
arter}',  c.  Its  extent  is  limited  by  the  base  of  the  little  toe  in  one  direc- 
tion, and  the  back  of  the  first  interosseous  space  in  the  other.  Internally 
it  joins  the  dorsal  artery  of  the  foot  (anterior  tibial)  by  means  of  the  com- 
municating branch,  o,  so  as  to  establish  a  direct  inosculation  between  the 
main  vessels  on  the  fore  and  hinder  aspects  of  the  leg.  In  this  course  it 
crosses  three  of  the  metatarsal  bones  near  their  tarsal  ends,  and  rests  on 
most  of  the  interossei  muscles.  At  the  outer  part  it  is  covered  by  the 
flexor  perforans  and  the  lumbricales,  and  at  the  inner,  by  the  adductor 
j^ollicis. 

Companion  veins  lie  on  its  sides,  and  the  external  plantar  nerve  curves 
in  a  similar  way  just  behind  it. 

From  the  convexity  or  anterior  part  of  the  arch  proceed  digital  arte- 
ries, and  from  the  concavity  arise  perforating  and  small  nutritive  branches. 

The  digital  branches,  four  in  number,  are  furnished  to  the  three  outer 
toes  and  half  the  second.     Each,  except  the  most  external,  splits  at  the 


202  ILLUSTRATIONS    OF   DISSECTIONS. 

cleft  of  the  toes  to  supply  the  contiguous  sides  of  two;  and  at  the  point 
of  division  springs  a  small  branch  {anterior  perforating),  which  passes 
downwards  to  anastomose  with  the  interosseous  arteries  on  the  dorsum  of 
the  foot.  Whilst  they  lie  on  the  interossei  small  offsets  are  emitted  to 
those  muscles. 

The  first  branch,  d,  lying  on  the  outside  of  the  small  toe,  remains 
single  to  the  end  of  the  digit,  and  supplies  cutaneous  branches  to  the  outer 
part  of  the  foot,  like  the  nerve. 

The  second,  i,  placed  over  the  fourth  interosseous  space  may  commu- 
nicate with  the  former  by  a  cross  piece  (Plate  lvii.);  it  gives  an  offset  to 
the  fourth  lumbricalis,  and  branches  for  the  sides  of  the  fifth  and  fourth 
digits. 

The  third  corresponds  with  the  third  space,  and  furnishes  offsets  to 
the  third  lumbricalis  and  the  transversalis  pedis:  its  two  terminal  pieces 
belong  to  the  sides  of  the  fourth  and  third  toes. 

The  fourth  may  supply  the  second  lumbricalis;  and  it  ends  on  the 
sides  of  the  third  and  second  digits. 

On  the  toes  the  arteries  are  continued  to  the  extremity,  one  on  eacli 
side;  and  they  unite  in  an  arch  on  the  plantar  surface  of  the  last  phalanx, 
from  which  fine  branches  are  sent  to  the  tip  of  the  digit.  At  the  extremity 
of  the  second  toe  the  branch  derived  from  the  plantar  arch  anastomoses 
with  the  digital  branch,  /,  of  the  dorsal  artery  of  the  foot.  Whilst  the 
arteries  lie  on  the  sides  of  the  digits  they  furnish  superficial  offsets  forwards 
and  backwards,  and  communicate  beneath  the  flexor  tendons  by  means  of 
cross  branches  behind  the  inter j)halangeal  articulations,  as  in  the  fingers. 

Three. posterior  jjerf orating  branches,  s,  pass  down  from  the  arch  be- 
tween the  lateral  attachments  of  the  dorsal  interossei  muscles  of  the  outer 
three  spaces,  and  anastomose  with  t  he  interosseous  arteries  on  the  dorsum 
of  the  foot. 

Some  small  nutritive  and  muscular  branches  take  their  origin  from 
the  arch,  and  from  the  digital  arteries. 

The  external  plantar  artery  of  the  foot  answers  to  the  ulnar  artery  of 
the  hand;  it  resembles  that  vessel  in  furnishing  digital  branches  to  three 
toes  and  a  half,  and  in  forming  an  arch  which  commanicates  internally 
with  the  other  leading  vessel  of  the  limb. 

But  the  following  marked  differences  exist  in  the  mode  of  ending  of 
the  two  main  bloodvessels  of  the  limbs.  In  the  foot  there  is  but  one  arch 
in  which  both  tibials  are  united;  and  the  plantar  arch  thus  formed  has  a 


ANTERIOR   TIBIAL    ARTERY.  20S 

deep  position  in  the  sole  of  the  foot,  where  it  lies  in  contact  with  tlie  iii- 
terossei.  In  the  htmd  on  -the  contrary  there  are  two  distinct  palmar 
arches — superficial  and  deep,  which  communicate  through  the  interven- 
tion of  small  branches:  of  these,  the  former  is  continuous  with  the  ulnar 
artery,  and  the  latter  with  the  radial. 

On  comparing  also  the  muscular  offsets  of  the  arterial  trunks  in  the 
hand  and  foot  considerable  dissimilarity  will  be  found,  as  in  the  nerves, 
on  account  of  the  want  of  uniformity  in  the  muscles  of  the  two  parts. 

Wounds  of  the  plantar  arch  can  take  place  but  seldom  in  consequence 
of  the  vessel  being  protected  by  the  shoe,  and  the  depth  of  the  soft  parts. 
If  it  was  opened  it  would  bleed  freely,  as  in  injury  of  the  palmar  arch, 
from  its  free  inosculation  with  the  anterior  tibial  artery. 

With  bleeding  from  a  wound  in  the  foot,  such  as  would  lead  to  the 
supposition  that  the  arch  itself,  or  one  or  more  of  the  digital  arteries  close 
to  their  origin  from  it  had  been  opened,  the  flow  of  blood  would  generally 
be  arrested  by  pressure  applied  to  the  anterior  tibial  artery  on  the  dorsum 
of  the  tarsus,  to  the  posterior  tibial  between  the  heel  and  ankle,  and  to 
the  wound  in  the  foot  by  a  graduated  compress,  as  in  the  case  of  wounds 
of  the  palm  of  the  hand.  Should  considerable  recurrent  bleeding  still 
take  place,  ligature  of  one  or  both  of  the  tibials  may  be  tried,  to  cut  off 
the  free  supply  of  blood  to  the  foot. 

Dorsal  artery  of  the  foot,  I.  This  artery  is  a  continuation  of  the  an- 
terior tibial  trunk  (Plate  lviii.),  and  furnishes  digital  branches  to  one 
toe  and  a  half.  It  enters  the  sole  at  the  back  of  the  first  interosseous 
space,  and  ends  by  joining  the  plantar  arch  through  the  communicating 
part,  0.  Prom  its  extremity  in  the  sole  of  the  foot  the  large  artery  of  the 
great  toe  is  sent  forwards,  and  one  or  two  small  branches  run  back- 
wards. 

The  large  artery  of  the  toe,  n  (art.  mag.  pol.),  is  the  digital  branch 
of  the  anterior  tibial,  and  supplies  one  toe  and  a  half:  it  has  the  following 
arrangement.  It  runs  forwards  over  the  first  interosseous  muscle  to  the 
cleft  of  the  toes,  where  it  splits  into  the  two  collateral  branches  for  the  great 
toe  and  the  next;  and  near  the  fore  part  of  the  interosseous  space  a  brancli 
is  directed  inwards  under  the  flexor  muscles,  or  between  the  heads  of  the 
short  flexor,  to  form  the  digital  branch,  e,  of  the  inner  side  of  the  great 
toe. 

The  anterior  tibial  artery  in  the  foot  resembles  the  radial  artery  in  the 
hand  in  supplying  branches  to  one  digit  and  a  half.     But  it  differs  fro' 


204:  ILLDSTKATIOJSIS    OF    DISSECTIONS. 

that  vessel  in  assisting  to  complete  the  plantar  arch  instead  of  forming 
like  the  radial,  a  separate  arch. 

Deep  anastomosis  of  the  foot.  In  the  sole  of  the  foot  amongst  the  pro- 
cesses of  the  tendons  and  the  ligaments  is  situate  a  chain  of  anastomoses 
between  branches  of  the  internal  and  external  plantar  with  the  dorsal 
artery  of  the  foot,  as  is  shown  in  the  Drawing. 

External  plantar  nerve,  3.  In  this  dissection  of  the  nerve  the 
branches  to  the  interossei  are  traced  out.  From  the  part  of  the  nerve  by 
the  side  of  the  plantar  arch  small  muscular  offsets  are  supplied  to  all  the 
interossei  muscles:  these  are  so  evident  as  not  to  require  figures  of  refer- 
ence. The  remaining  muscular  branches  of  this  part  of  the  nerve  have 
been  described  with  Fig.  i. 


DESCRIPTION  OF  PLATE  LVIII. 


The  dissection  of  the  front  of  the  leg  and  dorsum  of  the  foot  appears 
in  this  Illustration. 

In  preparing  the  dissection  divide  the  skin  along  the  centre  of  the 
imb,  and  reflect  it  to  the  sides  by  means  of  a  cross  cut  at  each  end,  and 
a  third  opposite  the  ankle.  After  search  has  been  made  for  the  cutaneous 
nerves  and  vessels  in  the  fat,  the  fascia  may  be  taken  away  to  show  the 
muscles  and  the  deeper  vessels  and  nerves;  but  in  executing  this  step  the 
two  parts  of  the  anterior  annular  ligament  are  to  be  defined  and  left, 
as  in  the  Plate. 

CUTANEOUS  VEINS  AND  ARTERIES. 

On  the  dorsum  of  the  foot  is  the  arch  in  which  the  saphenous  veins 
begin.  The  small  arteries  ramifying  on  the  surface  of  the  leg  ^nd  foot 
are  derived  from  the  anterior  tibial  trunk. 


a.  Venous  arch  of  the  foot. 
h.  Internal  saphenous, 
c.  External  saphenous. 


d.  Communicating  veins. 
j9.  Venae  comites. 


The  venous  arch,  a,  on  the  dorsum  of  the  foot,  answers  to  a  similar 
arch  on  the  back  of  the  hand.     Contained  in  the  subcutaneous  fat,  it  is 


PLATE  LVI 


CUTANEOUS    NEKVES    OF    THli    FKOXT    OF    THE    LEG.  205 

placed  .Ulterior  to  the  tarsus.  Its  convexity  is  turned  towards  the  toes, 
and  is  joined  by  small  digital  veins;  and  at  its  concavity  open  small  super- 
ficial, with  some  deep  veins,  d.  At  eacli  end  the  arch  is  continued  into 
a  saphenous  vein. 

The  internal  saphenous  vein,  h,  begins  at  the  inner  end  of  the  dorsal 
arch,  and  ascending  to  the  leg  in  front  of  the  inner  ankle  crosses  ob- 
liquely the  tibia:  its  further  course  in  the  leg  behind  that  bone  is  mani- 
fest in  Plate  lv. 

The  external  saphenous  vein,  c,  springs  from  the  confluence  of  the 
outer  end  of  the  arch  with  a  vein  from  the  outer  side  of  the  foot:  it  soon 
bends  below  the  outer  ankle  to  the  back  of  the  leg,  where  it  is  represented 
in  Plate  liii. 

Cutaneous  arteries.  In  the  leg  these  are  small  in  size,  and  are  offsets 
of  the  anterior  tibial,  but  as  they  are  unnamed  no  letters  of  reference 
have  been  placed  on  them.  They  issue  mostly  along  the  borders  of  the 
tibialis  anticus,  and  those  along  the  outer  side  of  the  muscle  mark  the 
position  of  the  subjacent  tibial  trunk.  One  larger  than  the  rest,  and 
external  to  them,  pierces  the  fascia  outside  the  extensor  of  the  toes,  B, 
and  runs  with  the  musculo-cutaneous  nerve,  3. 

On  the  dorsum  of  the  foot  and  toes  the  other  small  unnamed  arteries 
originate  in  the  dorsal  artery  of  the  foot  and  its  branches. 


CUTANEOUS  NERVES  OF  THE  FRONT  OF  THE  LEG. 

On  the  dorsum  of  the  foot,  as  on  the  back  of  the  hand,  there  is  a  free 
distribution  of  cutaneous  nerves;  whilst  the  teguments  on  the  fore  part 
of  the  leg,  like  those  on  the  back  of  the  forearm,  are  but  sparingly  sup- 
plied with  nerves. 


1.  Internal  saphenous. 

2.  External  saphenous. 

3.  Musculo-cutaneous. 


4.  Cutaneous  of  external  popliteal. 

5.  Cutaneous  of  anterior  tibial. 


The  internal  saphenous,  1,  courses  along  the  inner  side  of  the  leg 
(Plate  LV.),  and  sends  forwards  many  fine  branches  to  the  teguments 
over  the  tibialis  anticus:  the  largest  of  these,  near  the  knee,  is  .marked 
thus,  f.  Below  the  middle  of  the  leg  it  turns  to  the  fore  part  of  the 
ankle  with  the  saphenous  vein  to  end  in  the  teguments  of  the  inner  side 


206  ILLUSTRATIONS    OF   DISSECTIONS. 

of  the  instep,  reaching  about  two-thirds  along  the  foot.  Kear  the  end- 
ing it  is  joined  by  the  niusculo-cutaneous;  and  some  of  the  terminal 
filaments  sink  through  the  fascia,  like  the  musculo-cutaneous  nerve  in 
the  forearm,  to  supply  the  tarsus. 

The  external  saphenous,  2,  a  branch  of  the  internal  popliteal  trunk 
(p.  165),  descends  along  the  back  of  the  leg  to  the  heel  (Plate  liii.). 
Bending  forwards  below  the  external  malleolus,  it  runs  along  the  outer 
border  of  the  foot,  and  terminates  on  the  outside  of  the  little  toe.  When 
in  contact  with  the  foot  it  furnishes  nerves  to  all  the  outer  margin,  but 
the  offsets  to  the  sole  are  larger  than  those  on  .the  dorsum.  Oftentimes 
the  nerve  is  large;  then  it  supplies  more  digits  than  usual,  and  a  larger 
part  of  the  dorsum  of  the  foot. 

The  musculo-cutaneous  nerve,  3,  is  one  of  the  terminal  pieces  of  the 
external  popliteal  trunk  (p.  175),  and  takes  partly  a  deep  and  partly  a 
superficial  position  in  the  limb,  so  as  to  give  branches  to  muscles  and  in- 
teguments— whence  the  name.  Beginning  at  the  back  of  the  limb,  it  is 
directed  forwards  at  first  outside  the  fibula  and  under  theperoneus  longus. 
In  front  of  that  bone  it  is  inclined  down  between  the  peronei  muscles  and 
tlie  extensor  longus  digitorum;  and  gradually  reaching  the  surface,  it 
pierces  the  fascia  in  the  lower  third  of  the  leg  to  end  on  the  dorsum  of 
the  foot  and  toes. 

When  the  nerve  is  beneath  the  fascia  it  furnishes  offsets  to  the  pero- 
neus  longus  and  brevis  muscles. 

After  it  becomes  cutaneous  it  divides  into  two  pieces,  inner  and  outer, 
which  are  continued  over  the  dorsum  of  the  foot  to  the  extremities  of  the 
toes,  like  the  radial  nerve  on  the  hand.  These  two  branches  may  vary 
much  in  size  and  in  distribution;  but  commonly  they  supply  dorsal  digital 
nerves  to  all  the  toes,  except  the  outer  side  of  the  little  toe,  and  the  con- 
tiguous sides  of  the  gi'eat  and  second  toes.  Each  of  the  two  primary  pieces 
furnishes  offsets  to  its  sides  of  the  foot,  and  communicates  with  the  saphe- 
nous nerve  close  to  it. 

Anterior  tibial  nerve,  8.  At  the  back  of  the  first  interosseous  space 
this  nerve  becomes  cutaneous;  and  it  ends  in  two  dorsal  digital  nerves  for 
the  adjacent  sides  of  the  first  and  second  toes.  Offsets  of  it  enter  the 
teguments  of  the  first  interosseous  space;  and  it  is  joined  by  the  musculo- 
cutaneous nerve. 

.Cutaneous  of  the  external  popliteal,  4.  Arising  from  the  external 
popliteal  at  the  back  of  the  limb,  and  piercing  the  fascia,  it  is  distributed 


■TIBIALIS    ANTICUS    MUSCLE. 


207 


111  the  integuments  of  the  fore  and  outer  jmrts  of  the  leg  as  low  as  the 
t^pot  at  Avhich  the  niusculo-cutaneous  makes  its  appearance. 


MUSCLES  OF  THE  FRONT  OF   THE  LEG. 

Two  groups  of  muscles  come  into  view  in  this  Illustration:  an  ante- 
rior which  bends  the  ankle  and  extends  the  toes;  and  a  lateral  for  the 
extension  of  the  ankle. 


A.  Tibial!  anticus. 

B.  Extensor  longus  digitorum. 

C.  Extensor  longus  poUicis. 

D.  Peroneus  tertius. 

F.  Extensor  brevis  digitorum. 
H.  Peroneus  longus. 


I.    Peroneus  brevis. 
J.    Upper    part     of     annular     liga- 
ment. 
K.  Lower  part  of  annular  ligament. 
N.  External  annular  ligament. 
O.  Sheaths  for  the  peronei. 


Anterior  group  of  muscles.  Between  the  tibia  and  fibula  are  lodged 
two  flexors  of  the  ankle  (tibialis  and  peroneus  tertius);  and  between  them 
are  situate  the  long  extensor  of  the  toes  and  the  special  extensor  of  the 
great  toe.     On  the  dorsum  of  the  foot  lies  the  short  extensor  of  the  toes. 

The  tibialis  anticus,  A,  is  the  widest  and  most  internal  muscle  of  the 
group.  Its  origin  is  fixed  to  the  upper  half  or  rather  more  of  the  outer 
surface  of  the  tibia,  and  to  the  contiguous  part  of  the  interosseous  mem- 
brane— the  membranous  attachment  reaching  rather  lower  down  than  the 
osseous.  In  the  lower  third  of  the  log  the  muscle  acquires  a  tendon,  and 
passing  through  a  sheath  in  each  part  of  the  annular  ligament,  is  in- 
serted into  the  inner  surface  of  the  internal  cuneiform  bone,  and  the  base 
of  the  metatarsal  bone  of  the  great  toe. 

In  contact  with  the  fascia  throughout,  the  muscle  is  inseparably 
united  with  it  by  an  aponeurosis  at  the  upper  part.  It  rests  on  the  tibia 
and  the  interosseus  membrane,  covering  the  spine  of  that  bone  in  the 
lower  third  of  the  leg;  and  lies  over  the  ankle-joint  and  the  tarsus.  Its 
outer  border  touches  the  extensor  digitorum  and  extensor  pollicis,  and  is 
the  guide  to  the  anterior  tibial  vessels.  In  the  annular  ligament  the  ten- 
don is  surrounded  by  a  synovial  sac  which  reaches  nearly  to  the  insertion. 

With  the  foot  free  to  be  moved  the  muscle  will  bend  the  ankle  and 
carry  inwards  the  great  toe;  it  can  also  raise  the  inner  border  of  the  foot, 
drawing  inwards  this  part.     The  foot  being  fixed,  as  in  standing,  it  will 


208  ILLUSTRATIONS    OF    DISSECTIONS. 

help  the  tibialis  posticus  to  lift  the  inner  margin  of  the  instep,  so  as  to 
make  the  outside  of  the  foot  the  supporting  part  of  the  body. 

After  the  advanced  foot  has  reached  the  ground  in  walking,  the  mus- 
cle will  be  able  to  bring  the  tibia  forwards  over  the  instejo;  and  in  stoop- 
ing and  rising  it  will  assist  in  steadying  the  bones  of  the  leg. 

In  deformity  of  the  foot  with  inversion,  and  elevation  of  the  inner 
part  of  the  sole  from  the  ground,  the  tendon  of  the  tibialis  anticus  is 
shortened  and  prominent,  and  will  have  to  be  divided,  together  with 
others,  before  the  sole  can  be  brought  into  its  natural  position. 

The  peroneus  tertius,  D,  is  small,  and  is  generally  united  with  the 
extensor  longus  digitorum.  It  arises  from  the  lower  fourth  or  third  of 
the  inner  surface  (anterior  part)  of  the  fibula,  below  the  long  extensor  of 
the  toes,  and  from  the  lower  end  of  the  interosseous  membrane.  The 
tendon  varies  much  in  size,  like  the  fleshy  part  of  the  muscle,  and  is 
transmitted  through  a  sheath  in  the  loAver  j)art  of  the  annular  ligament 
with  the  long  extensor,  to  be  inserted  by  a  widened  extremity  into  the 
upper  part  of  the  base  of  the  fifth  metatarsal  bone. 

More  or  less  joined  with  the  long  extensor  of  the  toes,  it  is  superficial 
throughout,  and  is  separated  from  the  peroneous  brevis  behind  it  by  a 
piece  of  fascia  which  is  fixed  into  the  fibula.  Underneath  the  muscle 
lie  the  lower  portion  of  the  fibula,  the  ankle-joint,  and  the  short  extensor 
of  the  toes. 

When  the  foot  hangs  the  muscle  will  be  employed  as  a  flexor  of  the 
ankle,  like  the  tibiallis;  and  it  will  raise  the  outer  border  of  the  foot. 
But  should  the  limb  be  fixed  by  contact  with  the  ground,  the  action  of 
the  peroneus  tertius  on  the  leg  in  walking  and  stooping  will  be  the  same 
as  that  of  the  tibialis. 

The  extensor  longus  digitorum,  B,  is  a  thin  narrow  muscle,  which 
arises  from  the  head  and  three-fourths  of  the  inner  surface  (anterior  part) 
of  the  fibula;  from  the  external  tuberosity  of  the  tibia,  and  the  contigu- 
ous interosseous  membrane  (about  an  inch);  and  from  the  fascia  of  the 
leg.  Its  tendon  below  is  contained  in  a  sheath  in  the  lower  portion  of 
the  annular  ligament  with  the  peroneus  tertius,  and  divides  into  four 
pieces  for  insertion  into  the  four  outer  toes. 

On  the  back  of  the  toes  the  tendons  are  arranged  like  those  of  the  ex- 
tensor of  the  fingers.  For  example,  on  the  first  phalanx  there  is  a  fibrous 
expansion,  which  is  not  fixed  into  the  subjacent  bone,  and  is  formed  by 
pieces  of  the  long  and  short  extensors,  and  by  tendons  from  the  lumbricalis 


.EXTENSORS    OF   THE    DIGITS.  209 

and  interossei;  but  that  on  the  little  toe  does  not  receive  any  contribution 
from  tlie  sliort  extensor.  At  the  front  of  the  metatarsal  phalanx  the  ex- 
pansion divides  into  three  parts,  which  are  connected  with  the  two  remain- 
ing phalanges  in  this  manner: — The  short  central  piece  is  inserted  into 
the  base  of  the  middle  phalanx;  and  the  two  lateral  blend  into  one  at  tlio 
fore  part  of  the  middle,  and  are  inserted  into  the  base  of  the  last  phalanx. 
Opposite  the  two  nearest  phalangeal  joints  a  fibrous  slip  descends  on  each 
side  from  the  expansion,  to  blend  with  the  capsule  of  those  articulations. 

The  muscle  lies  partly  in  the  leg  and  partly  on  the  dorsum  of  the 
foot:  and  although  not  fixed  into  the  nearest  phalanx,  it  is  so  closely 
united  to  that  bone  by  the  other  tendinous  slips  joining  it,  as  to  be  able 
to  extend  the  metatarso-phalangeal  joint.  Like  the  tibialis  it  is  super- 
ficial throughout.  Along  the  inner  side  lie  the  tibialis  and  extensor  polli- 
cis  with  the  tibial  vessels  and  nerve:  and  on  the  outer  are  situate  the  two 
external  peronei,  but  separated  by  a  process  of  fascia. 

If  the  foot  and  toes  are  not  fixed  the  muscle  extends  the  phalangeal 
joints  from  root  to  tip,  separating  the  digits  at  the  same  time;  and  it 
raises  afterwards  the  foot  so  as  to  bend  the  ankle. 

Should  the  foot  rest  on  the  ground  with  the  fibula  slanting  backwards, 
that  bone  can  be  brought  forwards  over  the  foot  by  this  muscle.  In  stoop- 
ing and  rising  it  will  assist  the  tibialis. 

The  extensor  hrevis  digitorum,  F,  occupies  the  dorsum  of  the  foot, 
and  gives  tendons  to  the  four  inner  toes.  Thin  and  fleshy  behind,  it 
arises  from  the  outer  surface  of  the  os  calcis  near  the  fore  part,  and  from 
the  outer  end  of  the  lower  piece  of  the  anterior  annular  ligament.  At 
the  back  of  the  metatarsal  bone  it  divides  into  four  fleshy  bundles;  and 
from  these  proceed  tendons  to  join  the  common  expansion  on  the  dorsum 
of  the  first  phalanx  in  the  case  of  three  toes,  but  the  tendon  of  the  great 
toe  is  inserted  separately  into  the  base  of  the  nearest  phalanx. 

On  the  instep  the  muscle  is  covered  by  the  long  extensor  and  the  pero- 
neus  tertius;  and  the  inner  fleshy  belly,  larger  than  the  others,  is  detach- 
ed from  the  rest  of  the  muscle  for  a  considerable  distance.  The  tendons 
blend  with  those  of  the  long  extensor,  and  are  applied  to  the  outer  border. 

It  assists  the  long  extensor  in  straightening  the  toes,  and  directs  them 
somewhat  out  at  the  same  time. 

The  extensor  proprms  pollicis,  Q,  is  concealed  for  the  most  part  by 

the  preceding  muscle.     It  takes  origin  from  the  middle  three-fifths  of  the 

inner  surface  (anterior  part)  of  the  fibula,  and  from  the  interosseous  mem- 
14 


210  TLLUSTEA.TIONS    OF    DISSECTIONS. 

brane.  At  tlie  ankle  it  ends  in  a  tendon,  which  is  contained  in  a  space 
in  tlie  lower  piece  of  the  annular  ligament,  and  is  thence  directed  over 
the  inner  part  of  the  foot  to  be  inserted  into  the  base  of  the  last  phalanx 
of  the  great  toe. 

The  part  of  the  muscle  in  the  leg  is  deeply  placed  between  the  exten- 
sor longus  digitorum  and  the  tibialis;  but  the  tendon  on  the  dorsum  of 
the  foot  is  superficial.  The  tibial  vessels  lie  inside  the  extensor  as  low  as 
tlie  ankle,  but  afterwards  outside  it. 

As  this  muscle  passes  over  the  ankle,  like  the  extensor  of  the  digits,  it 
has  a  similar  action,  viz.  first  straightening  its  digit  and  next  bending  the 
the  ankle.  And  the  slanting  limb  touching  the  ground,  the  extensor  of 
the  great  toe  will  help  to  move  the  fibula  over  the  foot-:  or  to  support 
that  bone  in  stooping. 

The  anterior  annular  ligament  of  the  leg  is  constructed  by  the  deep 
fascia  strengthened  by  transverse  fibres  near  the  ankle-joint.  It  incases 
and  binds  down  the  tendons  of  the  muscles,  and  consists  of  two  parts- 
upper  and  lower. 

The  upper  piece,  J,  is  placed  above  the  ankle,  and  is  squarer  in  form 
than  the  lower.  It  is  attached  laterally  to  the  tibia  and  fibula,  and  is  con- 
tinued into  the  fascia  of  the  leg  by  the  upper  and  lower  edges.  In  it. is 
one  sheath  towards  the  inner  side  for  the  tibialis  anticus,  and  this  is  lined 
by  a  synovial  sac,  which  is  prolonged  on  the  tendon  into  the  other  part 
cf  the  ligament;  whilst  the  other  muscles  of  the  leg  pass  under  it  with- 
out being  contained  in  sheaths.  This  band  serves  the  purpose  of  fixing 
tlie  vertical  parts  of  the  long  muscles  to  the  front  of  the  ankle,  so  as  to 
render  them  able  to  bend  that  joint. 

The  lower  piece,  K,  is  wide  and  thin  internally  but  pointed  and 
thick  externally,  and  lies  below  the  level  of  the  ankle  on  the  outer  side. 
Externally  it  is  fixed  into  the  upper  surface  of  the  os  calcis  close  to  the 
interosseous  ligament,  and  internally  into  the  tibial  malleolus  and  the 
plantar  fascia;  and  it  blends  with  the  deep  fascia  by  its  edges.  Three 
sheaths  for  tendons  are  constructed  in  it;  an  inner  for  the  tibialis  anticus, 
an -outer  for  the  extensor  longus  digitorum  and  peroneus  tertius,  and  an 
intermediate  one  for  the  extensor  p-oprius  poUicis.  A  synovial  sac  lubri- 
cates each  sheath,  and  the  inner  one  is  continued  into  the  compartment 
in  the  upper  piece,  J,  of  the  ligament.  The  use  of  this  part  is  to  bind 
horizontally  the  tendons  of  the  long  extensors  to  the  foot,  in  order  that 
they  may  act  on  the  ankle  as  well  as  the  digits. 


I^ATEEAL    PEP;ONEI    MUSCLES.  211 

Lateral  muscles  of  the  leg. — Two  muscles  enter  into  this  group; 
and  as  tliey  are  attached  to  the  iibuhi  tliey  are  named  peronei. 

The  pcroneus  lojigus,  H,  tlie  highest  and  most  superficial  of  the  two, 
arises  from  the  outer  or  anterior  surface  of  the  upper  half  of  the  fibula, 
though  gradually  diminishing  in  width  downwards;  from  the  external 
border  of  tliat  bone  by  thin  fleshy  fibres  behind  the  peroneus  brevis,  as 
low  as  the  inferior  fifth;  and  from  the  fascia  incasing  the  muscle.  Its 
long  tendon  passes  through  an  annular  ligament  behind  the  outer  mal- 
leolus, and  through  a  separate  sheath  of  fibro-cartilage,'  0,  on  the  outer 
side  of  the  os  calcis  to  reach  its  insertion  in  the  sole  of  the  foot  (p.  200). 

Superficial  in  the  leg  it  rests  on  the  fibula  and  the  peroneus  brevis, 
concealing  altogether  this  muscle  above,  but  only  in  part  below.  By 
means  of  the  sheath  attaching  it  to  the  bones  the  peroneus  can  move  both 
the  ankle-joint  and  the  foot.  In  the  sole  of  the  foot  it  lies  deeply,  and 
is  received  into  a  third  fibrous  sheath  (Plate  LVii.,  Fig.  2,  Q). 

The  muscle  is  able,  when  the  foot  is  unsupported,  to  extend  the  ankle, 
and  to  raise  the  outer  border  of  the  instep,  depressing  at  the  same  time 
the  inner  edge  of  the  great  toe. 

The  foot  being  immovable  the  peroneus  longus  will  elevate  the  outer 
border,  throwing  the  weight  of  the  body  on  the  inner  side;  and  in  rising 
from  stooping  it  will  help  to  bring  back  the  fibula  to  a  right  angle  with 
the  foot. 

The  peroneus  hrevis,  1,  is  attached  to  the  outer  or  anterior  surface  of 
the  fibula  for  the  lower  two-thirds  of  the  shaft — the  upper  end  being 
pointed  and  lying  inside  its  fellow;  and  from  the  intermuscular  septum 
between  it  and  the  anterior  muscles  of  the  leg.  At  the  ankle  its  tendon 
passes  with  that  of  the  peroneus  longus  through  the  external  annular  liga- 
ment, lying  next  the  bone;  escaped  from  this  it  is  received  into  a  sheath, 
0,  on  the  outer  side  of  the  os  calcis,  above  that  for  the  peroneus  longus; 
and  it  is  finally  inserted  by  a  widened  end  into  the  base  of  the  metatarsal 
bone  of  the  little  toe. 

In  the  leg  the  lower  part  of  this  peroneus  is  superficial  in  front  of  the 
other,  and  its  tendon  is  connected  to  the  fibula  and  the  tarsus  by  sheaths 
like  those  of  its  companion.  Fascia  isolates  it  from  the  muscles  on  the 
front  and  back  of  the  leg. 

This  muscle  extends  the  ankle,  and  moves  the  foot  outwards  almost 
horizontally  when  the  toes  are  not  supported;  but  when  the  foot  is  fixed, 
as  in  standing,  it  will  assist  the  long  peroneus  in  raising  the  outer  border 


212 


ILLUSTKATIONS    OF    DISSECTIONS. 


from  the  ground.     In  rising  from  stooping  it  acts  on  the  fibula  like  the 
peroneus  longns. 

External  annular  ligament,  IST.  This  is  a  thin  band  beliind  and 
rather  below  the  fibular  malleolus,  which  is  formed  by  thickened  fascia, 
like  the  other  annular  ligaments  near  the  ankle.  In  front  it  is  attached 
to  the  malleolus,  and  behind  to  the  os  calcis.  Its  upper  end  joins  the  fas- 
cia of  the  leg,  and  the  lower  is  united  by  a  thin  fibrous  layer  to  the  bands 
of  fibro-cartilage  fixing  the  tendons  of  the  peronei  to  the  os  calcis.  There 
is  but  one  space  in  the  ligament,  and  this  lodges  the  two  peronei;'  it  is 
lubricated  by  a  synovial  sac,  which  bifurcates  inferiorly — a  piece  being 
continued  with  each  tendon  into  the  fibro-cartilaginous  sheath. 


ANTERIOR  TIBIAL  VESSELS. 

The  anterior  tibial  artery  with  its  venas  comites  extends  through  the 
front  of  the  leg  to  the  sole  of  the  foot. 


e.  Cutaneous  branch  with  a  nerve. 
/.  Offsets  of  the  recuiTent  branch. 
g.  Anterior  tibial  trunk. 
7i.  Dorsal  artery  of  the  foot. 
i.  Internal  malleolar  branch. 


j.   Anterior  peroneal  branch. 

k.  Tarsal  branch. 

I.   First  dorsal  interosseous. 

n.  Metatarsal  branch. 

o.  Three  outer  interosseous. 


The  anterior  tibial  artery,  g,  is  derived  from  the  splitting  of  the  pop- 
liteal trunk  at  the  lower  edge  of  the  popliteus  muscle;  and  it  reaches  to 
the  sole  of  the  foot,  which  it  enters  through  the  hinder  part  of  the  first 
interosseous  space,  ending  as  before  said  (p.  203).  Beginiiiug  at  the  back 
of  the  leg  (Plate  lv.)  it  is  directed  forwards  at  first  between  the  bones 
and  above  the  interosseous  membrane,  and  then  along  the  front  of  the  leg 
and  the  dorsum  of  the  foot.  A  l---^  on  'he  surface  of  the  limb  from  the 
inner  part  of  the  neck  of  the  fibula  to  the  first  interosseous  space  would 
mark  the  position  of  the  subjacent  vessel.  For  the  purpose  of  description 
a  division  of  it  into  two  is  commonly  made,  viz.  an  upper  part  called 
anterior  tibial,  and  a  lower,  which  has  been  named  the  dorsal  artery  of 
the  foot. 

In  the  leg  the  anterior  tibial  is  deeply  placed  between  the  fleshy  bellies 
of  the  muscles;  but  it  becomes  more  su^^erficial  near  the  ankle,  and  is 
covered  finally  only  by  the  annular  ligament  and  the  teguments.  To  its 
inner  side  nearly  all  the  way  is  the  tibialis  anticus;  though  close  to  the 


ANTEEIOR    TIBIAL    VESSELS.  213 

lower  end  the  extensor  proprius  pollicis  intervenes  between  the  two, 
having  crossed  the  artery  just  above  the  ankle.  On  the  outer  side  comes 
first  the  extensor  longus  digitoruni  for  about  two  inches,  then  the  exten- 
sor pollicis  as  far  as  the  ankle,  and  finally  the  extensor  longus  digitorum 
again  at  the  ending.  It  rests  in  the  upper  two-thirds  of  its  course  on 
the  interosseous  membrane,  and  in  the  lower  third,  on  the  tibia  and  the 
ankle-joint. 

Companion  veins,  p,  encircle  the  artery,  forming  a  plexiform  disposi- 
tion over  the  upper  part.  The  anterior  tibial  nerve,  6,  comes  into  con- 
tact with  the  vessels  about  the  place  of  meeting  of  the  upper  and  middle 
thirds  of  the  leg,  and  runs  with  them  to  the  foot;  at  first  it  is  external, 
then  internal  to  the  vessels,  and  finally  external  in  position  on  the  dor- 
sum of  the  foot. 

Branches.  Most  of  the  collateral  offsets  are  unnamed,  and  are  dis- 
tributed to  the  neighboring  muscles  and  the  teguments.  Even  the 
named  branches  are  small  in  size,  like  the  offsets  of  the  arteries  of  the 
upper  limb;  they  are  the  following: — 

The  recurrent  hranch  springs  from  the  upper  end  of  the  artery,  and 
ascends  through  the  tibialis  to  the  knee-joint:  it  gives  branches  to  that 
muscle,  and  its  superficial  ramifications  are  marked  with/. 

K  cutaneous  hrancli,  e,  accompanies  the  musculo-cutaneous  nerve:  it 
supplies  the  contiguous  muscles,  and  ends  in  the  teguments. 

Malleolar  hraoiches.  Two  small  arteries  with  this  name  take  origin  a 
little  above  the  ankle,  and  ramify  over  the  malleoli:  the  inner  is  shown 
by,  /;  and  the  outer,  concealed  by  the  muscles,  joins  the  anterior  com- 
municating branch,  j,  of  the  peroneal  artery  (p.  183). 

Articular  hranches  j^ass  from  the  lower  end  of  the  artery  into  the 
ankle-joint. 

Peculiarities.  Occasionally  the  trunk  of  the  anterior  tibial  artery 
has  been  found  superficial  to  the  muscles  in  the  lower  part  of  the  leg;  in 
such  a  condition  of  the  vessel  a  sujjerficial  wound  might  lay  itoiDcn.  Its 
size  is  very  varial)le,  like  the  arteries  of  the  u^oper  limb,  and  the  deficient 
part  is  supplied  by  an  offset  from  the  posterior  tibial,  or  from  the  pero- 
neal artery. 

Dorsal  artery  of  tliefoot,  h.  This  part  of  the  anterior  tibial  extends 
from  the  ankle-joint  to  the  ending  in  the  sole  of  the  foot.  It  lies  near 
the  surface;  and  its  position  will  be  found  by  the  line  before  mentioned. 

For  the  greater  part  of  its  extent  it  is  covered  by  the  inner  piece  of 


214  ILLUSTRATIONS    OF    DISSECTIONS. 

the  extensor  brevis  digitorum,  but  at  the  beginning  and  ending  only  by 
the  special  fascia  and  the  teguments.  It  is  firmly  supported  by  the 
subjacent  tarsal  bones.  Laterally  it  has  a  tendon  on  each  side,  viz.  the 
extensor  pollicis  internally,  and  the  extensor  longus  digitorum  externally, 
but  both  are  at  a  distance  from  it — about  half  an  inch. 

The  venae  comites  have  the  same  arrangement  here  as  above,  and  the 
anterior  tibial  nerve  is  placed  on  the  outer  side. 

Branches.  Many  offsets  are  given  to  the  tarsal  and  metatarsal  por- 
tions of  the  foot:  those  leaving  the  inner  side  of  the  vessel  are  unnamed; 
and  those  on  the  outer  side,  which  are  rather  larger,  are  named  tarsal, 
metatarsal,  and  interosseous,  from  their  distribution. 

The  tarsal  hrancli,  h,  arises  opposite  the  scaphoid  bone,  and  is  directed 
beneath  the  extensor  brevis  digitorum  to  the  outer  part  of  the  tarsus;  it 
gives  branches  to  that  muscle,  and  anastomoses  with  the  arteries  before 
and  behind  it,  viz.  metatarsal,  n,  and  anterior  communicating  of  the  pero- 
neal, j. 

The  metatarsal  hrancli,  n,  leaves  the  trunk  at  the  fore  part  of  the  tar- 
sus, and  runs  outwards  across  the  base  of  the  metatarsal  bones  to  the  bor- 
der of  the  foot,  where  it  anastomoses  with  the  tarsal  and  external  plantar 
arteries.  In  its  course  it  lies  beneath  the  short  extensor,  and  forms  an 
arch,  from  the  fore  part  of  which  the  following  small  interosseous  arte- 
ries proceed : — 

The  dorsal  interossei,  o,  of  the  three  outer  spaces  spring  from  the 
metatarsal  branch,  and  run  forwards  to  the  cleft  of  the  toes.  Here  each 
bifurcates,  and  the  small  resulting  branches  are  continued  to  the  end  of 
the  toes  as  the  dorsal  digital  arteries:  the  most  external  furnishes  also  a 
branch  to  the  outer  side  of  the  little  toe.  From  the  beginning  of  each 
interosseous  branch  a  piece  descends  to  the  sole  of  the  foot  to  unite  with 
the  plantar  arch;  and  from  the  ending  springs  another  offset  to  enter  a 
digital  artery:  these  are  named  anterior  and  posterior  joerf orating  branches 
(p.  202). 

First  dorsal  interosseous  branch,  I,  arises  from  the  dorsal  artery  as  it 
is  about  to  sink  into  the  sole:  it  is  continued  forwards  in  the  first  space, 
in  the  same  manner  as  the  other  arteries,  and  divides  like  them  for  the 
sides  of  the  first  two  toes.     The  space  receives  offsets  from  it. 

Branch  of  the  peroneal  artery,  j.  The  anterior  communicating  branch 
of  this  artery  (p.  183)  comes  through  the  aperture  in  the  lower  part  of  the 
interosseous  membrane,  and  descends  in  front  of  the  outer  malleolus  to 


LIGATURE    OF   THE    TIBIAL    ARTERY.  215 

the  tarsus,  where  it  distributes  many  branches:  above  it  anastomoses 
with  the  external  malleolar,  and  below  with  the  tarsal  artery. 

Vence  comites.  The  anterior  tibial  veins  have  the  same  extent  and 
connections  as  the  artery,  and  end  above  in  the  popliteal  trunk:  in  their 
course  they  receive  branches  corresponding  with  those  of  the  artery. 
They  have  aplexiforni  disposition  around  the  tibial  bloodvessel,  especially 
above;  and  they  anastomose  with  the  internal  saphenous  vein. 

Peculiarities.  The  dorsal  artery  of  the  foot  is  subject  to  great  varia- 
tions in  its  position  and  size.  Frequently  it  forms  an  arch  under  the 
extensor  brevis  digitorum,  with  the  convexity  towards  the  outer  border 
of  the  foot.  Much  bleeding  from  a  wound  on  the  top  of  the  instep, 
towards  the  outer  part,  which  would  be  far  out  of  the  usual  line  of  the 
vessel,  would  suggest  the  probability  of  the  artery  being  opened  in  its 
unusual  situation. 

When  the  anterior  tibial  is  so  small  as  not  to  reach  to  the  lower  part 
of  the  leg  the  anterior  communicating  branch  of  the  peroneal  becomes 
the  dorsal  artery  of  the  foot,  and  takes  the  place  of  the  deficient  tibial 
trunk:  this  substituted  vessel  may  have  also  the  same  uncommon  curved 
course  on  the  dorsum  of  the  foot  as  the  anterior  tibial. 

Ligature.  In  the  dead  body  the  artery  is  easily  reached  in  conse- 
quence of  its  superficial  and  fixed  position;  and  the  operation  of  ligature 
may  be  practised  on  it  m  the  following  way: — ■ 

First,  the  position  of  the  vessel  is  to  be  ascertained  by  a  line  on  the  sur- 
face, from  the  centre  of  the  ankle  to  the  back  of  the  first  interosseous 
space. 

A  cut  in  that  line,  about  two  inches  in  length  and  nearer  the  inter- 
osseous space  than  the  ankle-joint,  is  to  divide  the  skin,  the  teguments, 
and  the  deep  fascia  covering  the  muscles. 

After  cutting  through  the  superficial  strata  the  inner  piece  of  the 
extensor  brevis  digitorum  comes  into  sight;  and  the  tendon  connected  with 
those  fleshy  fibres  serves  as  the  deep  guide  to  the  bloodvessels  issuing  from 
beneath.  In  the  bottom  of  the  wound  appears  the  anterior  tibial  nerve, 
Avhich  is  generally  outside  and  close  to  the  artery;  but  the  tendons  of  the 
long  extensors  of  the  digits  are  at  some  distance  from  the  vessels,  and  are 
not  visible. 

Opening  now  the  arterial  sheath,  and  detaching  the  venge  comites, 
the  thread  is  to  be  passed  around,  and  to  be  knotted  on  the  vessel  in  the 
usual  wav. 


216  ILLUSTEATIONS    OF   DISSECTIONS. 

Should  tlie  tibial  artery  have  the  unusual  course  on  the  dorsum  of  the 
foot,  which  has  been  above  cited  (p.  215),  no  bloodvessels  will  be  met 
with  by  the  usual  incision  in  the  line  of  the  artery;  but  if  the  cut  be 
made  to  reach  the  interosseous  space,  the  wandering  vessel  may  be  recog- 
nized coming  to  the  hinder  part  of  that  interval  to  enter  the  foot. 

Wound  of  the  artery.  Considerable  bleeding  would  follow  the  open- 
ing of  the  artery  on  the  dorsum  of  the  foot  on  account  of  the  free  com- 
munication of  the  anterior  with  the  posterior  tibial  bloodvessel.  For  the 
arrest  of  the  haemorrhage  two  plans  may  be  adopted.  According  to  the 
one,  two  ligatures  may  be  applied  to  the  vessel,  one  above,  and  the  other 
below  the  opening;  and  according  to  the  other,  m"essure  may  be  made  on 
the  trunk  of  the  artery,  and  to  the  wound,  whilst,  if  necessary,  the  flow 
of  blood  in  the  posterior  tibial  artery  may  be  checked  by  the  employment 
of  a  compress  to  that  trunk. 

Lympliatics  of  the  leg.  Only  a  summary  of  these  small  vessels  will 
here  be  given,  as  they  are  not  indicated  in  the  Figure.  There  are  super- 
ficial and  deep  lymphatics  with  the  bloodvessels,  as  in  the  upper  limb. 

In  the  superficial  set  are  two  groups,  one  with  each  saphenous  vein. 
The  lymphatics  with  the  short  saphenous  enter  the  popliteal  glands;  and 
those  with  the  long  saphenous  vein  open  into  the  inguinal  glands.  En- 
largement and  inflammation  consequent  on  disease  or  irritation  of  the 
lymphatics  on  the  opposite  borders  of  the  foot  would  affect  different 
glands. 

The  deep  lymphatics  run  along  the  main  arteries,  and  all  converge  to 
the  popliteal  glands.  In  connection  with  the  lymphatics  on  the  anterior 
tibial  artery  there  is  a  small  gland;  this  is  the  lowest  in  the  limb,  and  is 
to  be  found  about  half  way  down  the  leg. 


.  BRANCHES  OF  EXTERNAL  POPLITEAL  NERVE. 

The  three  terminal  branches  of  the  external  popliteal  nerve,  viz.  recur- 
rent tibial,  anterior  tibial,  and  musculo-cutaneous,  which  begin  between 
tiie  fibula  and  the  peroneus  longus,  are  met  with  in  the  dissection  of  the 
front  of  the  leg. 

5.  Recurrent  tibial  branch.  7.  Branch  to  short  extensor  of  the 

6.  Anterior  tibial  nerve.  toes  and  the  tarsus. 

8.  Cutaneous  part  of  anterior  tibial. 


BKANCUES    OF    EXTERNAL    POPLITEAL    NERVE.  217 

The  recurrent  tibial  branch,  5,  passes  under  the  extensor  longus  digi- 
corum,  but  over  the  tibial  vessels,  to  the  artery  of  the  same  name,  and 
ascends  through  the  tibialis  anticus  to  the  knee-joint. 

The  anterior  tibial  nerve,  Q,  is  directed,  like  the  preceding,  beneath 
the  long  extensor  of  the  toes,  and  meets  with  the  tibial  vessels  above  the 
middle  of  the  leg.  From  this  point  it  is  closely  applied  to  those  vessels, 
crossing  them  once  or  more;  and  continues  on  the  outer  side  of  the  dorsal 
artery  of  the  foot  till  this  bloodvessel  enters  the  sole.  Finally  it  pierces  the 
fascia,  and  ends  in  the  dorsal  teguments  of  the  great  toe  and  the  next. 

This  nerve  furnishes  offsets  to  all  the  muscles  of  the  front  of  the  limb 
below  the  knee.  It  supplies,  namely,  the  two  flexors  of  the  ankle  (tibi- 
alis anticus  and  peroneus  tertius) ;  the  common  extensors  of  the  toes  (ext. 
digit,  longus  and  brevis) ;  and  the  special  extensor  of  the  great  toe  (ext. 
prop,  pollicis).  To  the  tarsus  it  gives  a  large  branch,  7,  which  resembles 
much  in  appearance  the  nerve  distributed  to  the  back  of  the  wrist:  from 
this  branch  offsets  are  distributed  to  the  extensor  brevis  digitorum,  which 
covers  it,  as  well  as  to  the  underlying  bones  and  articulation. 

The  musculo- cutaneous  nerve,  3,  takes  a  downward  course  at  first  be- 
tween the  fibula  and  the  peroneus  longus,  H,  and  nextly,  between  the 
peroneus  brevis  and  the  extensor  longus  digitorum,  B,  to  become  cutane- 
ous at  the  lower  third  of  the  leg.  Its  ending  on  the  dorsum  of  the  foot 
and  the  toes  has  been  before  described  (p.  206). 

Before  the  nerve  pierces  the  deep  fascia  it  emits  branches  as  before 
said  to  the  two  lateral  peroneal  muscles. 


INDEX    TO    VOLUME    I. 


INDEX 


Abducens  nerve,  108,  120 
Abductor  indicis,  88 

minimi  digiti  nianus,  ■'^T 
pollicis  manus,  8G 
Acromial  thoracic  artery,  2;] 
Adductor  minimi  digiti  87 

pollicis,  86 
Anastomosis  of  arteries 
in  the  axilla,  23 
at  tlie  elbow,  46 
m  theliand,  81,  82,  89 
Anastomotic  arterj'  of  brachial.  4.") 
Anconeus  muscle,  94 
Annular  ligament  of  wrist,   i)()sterior, 

93 
Aperture  of  Eustachian  tube,  194,  217 
larynx,  196 
nares,  195 
casophagus,  196 
Aponeuros.'s  of  soft  palate,  197 
Arch,  palmar,  deep,  89 

superficial,  81 
palatine.  197 
of  subclavian,  154 
Arm,  dissection  of,  37 
Artery,  anastomotic  brachial,  4.") 
auricular  posterior,  150 
axillary,  5,  19 
brachial,  34,  41' 
buccal,  166 
carotid,  common,  146 
external,  149 
internal,  109,  184 
carpal,  ulnar,  anterior,  76 
posterior,  97 
radial,  anterior,  69 
posterior.  97 
central  of  the  retina,  113 
cervical  ascending,  156 
deep,  161 
occipital,  161 
ciliary  anterior,  113 
posterior,  113 


-Artery,  circumflex,  anterior,  8.  52 

posterior,  8.  52,  61 
companion   of   median    nerve, 

76 
crico-thyroid,  183 
dental  anterior,  178 
infei-ior,  165 
posterior,  160,  178 
digital  of  hand,  82,  89 
dorsal  of  index  finger,  97 
of  scapula,  23,  53 
of  tongue,  175 
of  thumb,  97 
of  wrist  radial.  69 
ixlnar.  97 
ethmoidal,  113 
facial,  149.  166,  183 
frontal,  113 
infra  orbital,  178 
intercostal  upper,  156 
interosseous  anterior,  76,  101 
posterior,  100 
of  hand,  89.  97 
labial  inferior,  166 
lachrymal,  113 
large  of  thumb,  89 
laryngeal  inferior,  192 
superior,  192 
lingual,  150,  175 
mammary  internal,  156 

external,  8 
masseteric,  166 
maxillary  internal,  149,  165 
median,  76 
meningeal,  large.  110,  166,  169 

small,  169 
metacarpal  ulnar,  76 
radial,  97 
mylo-hyoid,  106 
nasal,  113 

nutritious  of  humerus,  45 
occipital,  149,  161 
ophthalmic,  113 


224 


INDEX. 


Artery,  palatine  inferior,  183 
palmar  deep,  89 
palpebral,  113 
perforating,  of  hand,  89 
pharyngeal  ascending,  183 
profunda  cervical,  156,  161 

humeral,  45,  60 
radial,  68,  88 
ranine,  175 

recurrent  interosseous,  101 
radial,  69,  101 
ulnar,  76 
scapular  posterior,  130 
subclavian,  127,  154 
sublingual,  175 
submental,  150 
subscapular,  8,  23 
superficial  of  palm,  69 
supra  orbital,  113 

scapular,  130,  156 
temporal,  149 

deep,  166 
thoracic  acromial,  23 
alar,  8,  23 
long,  8,  23 
superior,  23 
thyroid  inferior,  156,  182 
superior,  149,  183 
tonsillitic,  183 
transverse  cervical,  131,  156 

facial,  149,  178 
tympanic,  184 
ulnar,  69,  74,  81 
vertebral,  109,  156,  161 
Articulation  of  laryngeal  cartilages,  204 
Arytsenoid  cartilages,  203 

muscle,  210 
Ascending  cervical  vessels,  156 

pharyngeal  vessels,  183 
Auditory  nerve,  108 
Auricular  artery,  posterior,  149 
nerve,  large,  133,  152 
posterior,  134 
Auriculo-temporal  nerve,  152,  170 
Axilla,  3 

dissection  of,  1 
Axillary  artery,  5,  19 
glands,  12 
plexus,  10 
sheath,  19 
vein,  9,  24 
Axis,  thyroid,  156 


Azygos  uvulss  muscle,  199 

Basilic- vein,  29,  40 
Biceps  humeralis,  18 
Blood-letting  at  elbow,  30 
Brachial  aponeurosis,  27,  38 

artery,  41 

plexus,  25,  189 

veins,  40 
Brachialis  anticus,  39 
Buccal  artery,  166 
nei-ve,  168 
Buccinator  muscle,  164 

Cardiac  nerves,  lovs^er,  188 
middle,  188 
upper,  188 
Carotid  arteiy,  common,  146 
external,  149 
internal,  109,  148,  184 
Carpal  arteries,  radial,  69,  97 

ulnar,  76 
Cartilage,  arytenoid,  203 
cricoid  203 
cuneiform,  204 
thyroid,  203 
triangular  nasal,  216 
Cartilages  of  nose,  216 

of  Santorini,  203 
of  trachea,  215 
of  Wrisberg,  204    . 
Cavernous  sinus,  116 
Central  artery  of  retina,  113 
Cephalic  vein,  24,  30,  40 
Cervical  ganglion,  inferior,  188 
middle,  188 
superior,  187 
nerves,  anterior,  161,  189 

posterior,  161 
plexus,  133,  189 

deep  branches,  189 
superficial,  133 
Cervico-facial  nerve,  140,  151 
Chiasma  of  optic  nerves,  106 
Chorda  tympani  nerve,  171 
Chordae  vocales,  206 
Ciliary  arteries,  113 

nerves,  nasal,  115 

lenticular,  119 
Circular  sinus,  116 
Circumflex  artery,  anterior,  8,  52 

posterior,  8,  52,  61 


INDKX. 


225 


Circumflex  nerve,  11,  53 
Conies  nervi  mediani,  77 
Commissure  of  optic  nerves,  106 
Complexus  muscle,  159 
Compression  of  arteries 
bracliial,  41 
femoral,  33 
subclavian,  128 
Constrictor  inferior,  191 
faucium,  199 
middle,  191 
superior,  191 
Coraco-bracliialis,  3,  18 

clavicular  ligament,  14 
Cords,  vocal,  206 
Cornicula  laryngis,  203 
Costo-coracoid  membrane,  19 
Cranial  nerves,  106 
Crico-arytsenoid  joint,  205 

muscle  lateral,  209 

posterior,  209 
thyroid  joint,  204 

membrane,  204 
muscle,  210 
Cricoid  cartilage,  203 
Cuneiform  cartilages,  204 

articulations  of,  205 
Cutaneous  nerves  of  arm,  74 
face,  179 

hand,  palm,  70,  77 
neck,  front,  140 
shoulder,  53 
thorax,  11 
Cutaneous  veins  of  elbow,  28 

Deep  cervical  artery,  156,  161 

facial  vein,  167 
Deglutition,  act  of,  192,  196 
Deltoid  muscle,  51 
Dental  artery,  anterior,  178 
inferior,  165 
posterior,  166,  178 
nerve,  anterior,  179 
inferior,  170 
posterior,  179 
Descendens  noni  nerve,  152,  158 
Depressor  epigiottidis,  211 
Digastric  muscle,  144 

nerve,  152 
Digital  arteries,  radial,  82,  89 
ulnar,  82 
nerves  of  median,  84 
15 


Digital  nerves  of  radial,  70 
of  ulnar,  84 
Dissection  of  arm,  back,  54 
front,  37 
axilla,  1 

axillary  vessels,  14 
base  of  skull,  104 
bend  of  elbow,  27 
brachial  plexus,  14 
carotid  artery,  common, 
141 
external,  141 
internal,  180 
cranial  nerves  in  neck,  181 
forearm,  back,  91,  98 
front,  63,  71 
hand,  back,  91 

palm,  79,  86 
larynx,  201 
neck,  back,  159 
front,  121 
neck,    anterior    triangle, 
141 
posterior  triangle, 
121 
nose,  215 
orbit,  110,  117 
pharynx,  190 
Xjterygoid  region,  156,  168 
scapula  muscles,  48 
shoulder,  48 
soft  palate,  192 
subclavian  artery,  153 
submaxillary  region,  173 
superior  maxillary  nerve, 

177 
upper  limb,  1 
Dorsal  artery  of  tongue,  175 

of  scapula,  23,  53 
Ductus  ad  nasum,  219 
Stenonis,  138 
Whartonii,  174 
Riviniani,  174 
Dura  mater  of  skull,  105,  116 
nerves  of,  106 
vessels  of,  105 

Eighth  cranial  nerve,  108 
Elbow  in  dislocation,  55,  65 
Eleventh  cranial  nerve,  108,  134,  187 
Epiglottis,  204 

articulation,  205 


226 


INDEX. 


Epiglottis,  use,  196,  204 
Ethmoidal  arteries,  113 
Eustachian  tube,  194,  217 
Extensor  carpi  radialis  brevis,  93 
longus,  93 
carpi  ulnaris,  94 
digiti  minimi,  94 
digitorum  communis,  93 
indicis,  100 
ossis  metacarpi,  99 
primi  internodii  pollicis,  99 
secundi     internodii     pollicis, 
99 
External  cutaneous  nerve  of  arm,  38 

mammary  artery,  8 
Ej^e,  arteries,  113 

muscles.  111,  118 
nerves,  115,  119 
veins,  113 

Facial  artery,  150,  166,  183 
nerve,  108,  151,  180 
vein,  166 
Falx  cerebelli,  105 

cerebri,  105 
Fascia,  brachial,  27,  38 
cervical,  137 
costo-coracoid,  19 
forearm,  27 
Fat  in  axilla,  13 

m  hollow  of  elbow,  67 
Fifth  cranial  nerve,  107 
First  cranial  nerve,  107,  221 
Flexor  nainimi  digiti,  87 
carpi  radialis,  64 
ulnaris,  64 
digitorum  profundus,  72,  80 

sublimis,  65,  79 
pollicis  longus,  71 
brevis,  £7 
Forearm,  dissection  of,  63 
front,  deep,  71 

superficial,  63 
back,  deep,  98 

superficial,  91 
Fossae  of  base  of  skull,  104 
Fourth  cranial  nerve,  107,  114 
Fracture  of  clavicle,  15 
Frontal  artery,  113 
nerve,  115 

Ganglia  cervical,  187 


Ganglion,  Gasserian,  107 
lenticular,  110 
ophthalmic,  119 
submaxillary,  17G 
Genio-hyo-glossus,  173 

hyoideus,  172 
Gland  lachrymal,  111 
parotid,  138 
sub-lingual,  139,  174 
submaxillary,  139 
Glands,  axillary,  12,  26 
cervical,  143 
submaxillary,  139,  174 
Glosso-pharyngeal  nerve,  108,  175,  185 
Glottis,  207 

Gustatory  artery,  166,  176 
nerve,  170,  176 

Hand,  dissection  of,  78 

back,  91 

palm,  78,  86 
Hollow  before  elbow,  66 
Humerus,  fracture  of,  52 
Hyo-glossus  muscle,  173 
Hyoid  bone,  201 
Hypoglossal  nerve,  lOD,  152,  175,  1S7 

Indicator  muscle,  ICO 
Inferior  maxillary  nerve,  169 
Infra-orbital  artery,.  178 
nerve,  180 
trochlear  nerve,  1 15 
Infra-spinatus  muscle,  50 
Innominate  artery,  154 

vein,  156 
Intercostal  artery,  superior,  156 
cutaneous  nerves,  11 
Intercosto-humeral  nerve,  12,  25 
Internal  cutaneous  of  arm,  25,  36 
Interosseous  arteries  of  hand,  89 

artery,  anterior,  76,  101 

posterior,  100 
muscles  of  hand,  88 
nerve,  anterior,  77 
posterior,  102 
Isthmus  faucium,  195 

of  thyroid  body,  214 

Jacobson'r  nerve,  185 
Jugular  vein  anterior,  140,  157 

external,  131,  151,  157 
internal,  151,  157 


INDEX. 


227 


Labial  arteiy,  inferior,  166 
Lachiymal  arteiy,  113 
duct,  219 
gland,  111 
nerve,  114 
Large  arterj^  of  thumb,  89 
Laryngeal  arteries,  192,  213 

nerve,  external,  186,  193 
inferior,  186,  212 
superior,  1S6,  211 
pouch, 207 
Larynx,  206 

aperture,  196 
articulations,  204 
cartilages,  202 
interior,  206 
muscles,  209 
mucous  membrane,  208 
nerves,  211 
ventricle,  207 
vessels,  218 
Lateral  cutaneous  nerves  of  thorax,  11 
Latissimus  dorsi,  2,  17,  49 
Lateral  sinus,  117 
Lenticular  ganglion,  119 
Levator  anguli  oris,  177 
scapulcB,  49,  123 
labii  superioris,  177 
palati,  198 

palpebr^  superioris,  112 
pharyngis,  191 
Liganienta  brevia,  80 
Ligaments  of  the  larynx,  204 
Ligamentum  stylo-maxillare,  171 
hyoidean,  173 
Ligature  of  arteries 

axillary,  6,  21 
brachial,  34,  42 
cai'otid,  common,  147 
external,  149 
internal,  148 
lingual,  150 
radial,  68 
subclavian,  third  part,  129 

second  pai"t,  156 
ulnar,  75 
Limb,  upper,  dissection  of,  1 
Lingual  artery,  150,  175 

vein,  175 

Longus  colli  muscle,  182 

Lurabricales  of  hand,  88 

Lymphatic  duct,  left,  157 

right,  157 


Lymphatics  of  arm,  47 
axilla,  13 
neck,  185 

Mammary  artery,  external,  8 

internal,  156 
Masseter  muscle,  164 
Masseteric  arteiy,  166 
nerve,  169 
Maxillary  arteiy,  internal,  150,  165 
nerve,  inferior,  167 
superior,  179 
Meatuses  of  the  nose,  218 
jMedian  basilic  vein,  29 
cephalic  vein,  29 
nerve,  47,  70,  84 
veins,  28 
Meningeal  vessels,  109,  166,  169 
nerves,  106 
veins,  110 
Metacarpal  artery,  76 
Motor  oculi  nerve,  107,  114,  120 
Movement  of  radius,  72 
Muscuio-cutaneous  nerve,  25 

spiral  nerve,  46,  61,  102 
Musculus  abductor  minimi  digiti,  8> 
indicis,  88 
pollicis,  86 
adductor  minimi  digiti,  87 

pollicis,  86 
anconeus,  94 
arytEenoideus,  210 
ary t£eno-epiglottideus  infer. , 

211 
azygos  uvulee,  199 
biceps  humeraiis,  18,  39 
brachialis  anticus,  39 
buccinator,  164 
circumflexus  palati,  198 
coniplexus,  159 
constrictor  inferior,  191 

isthmi     faucium, 

199 
medius,  191 
superior,  191 
coraco-brachialis,  3,  18 
crico-arytsenoideus  lateralibj 
209 
posticus, 
209 
crico-thyroideus,  210 
deltoides,  51 
depressor  epiglottidis,  211 


228 


INDEX. 


Musculus    digastricus,  144 

extensor  carpi  radialis  lon- 

gus,  93 
extensor  carpi  radialis  bre- 

vis,  93 
extensor  carpi  ulnaris,  94 
minimi  digiti,  94 
digitorum  manus, 

93 
indicis,  100 
ossis       metacarpi 

pollicis,  59 
primi      internodii 

pollicis,  99 
secundi  internodii 
pollicis,  59 
flexor  brevis  minimi  digiti, 
87 
carpi  radialis,  64 
ulnaris,  64 
pollicis  brevis,  87 
•longus,  71 
profundus  digit.,  72, 

80 
sublimis  digit. ,  65,  79 
genio-hyo-glossus,  173 

hyoideus,  172 
liyo-glossus,  173 
indicator,  .100 
infra-spinatus,  50 
interossei  manus,  88 
latissimus  dorsi,  2,  17,  49 
levator  anguli  oris,  177 

scapulas,    49, 
123 
labii  superioris,  177 
alae  nasi,  178 
palati,  198 
palpebrse,  113 
phai'yngis  externus, 
191 
internus, 
192 
uvulae,  199 
longus  colli,  182 
lumbricales  manus,  88 
massetericus,  164 
mylo-hyoideus,  145 
obliquus  capitis  infer.,  160 
super.,  160 
oculi  inferior,  118 
superior,  111 


Musculus    omo-hyoideus,  123,   144,  154 
opponens  minimi  digiti,  87 

pollicis,  86 
orbicularis       palpebrarum, 

177 
palato-glossus,  199 

pharyngeus,  199 
palmaris  brevis,  79 
longus,  64 
pectoralis  major,  2,  16 
minor,  2,  16 
pronator  quadratus,  73 
radii  teres,  63 
pterygoideus  externus,  164 
iiiternus,  164 
rectus  capitis  anticus  major, 
181 
minor,  182 
lateralis,  181 
posticus  major, 
160 
minor,  160 
oculi  externus,  112,  118 
inferior,  118- 
internus,  118 
superior,  113 
liiomboideus,  major,  49 
minor,  49 
salpingo-pharyngeus,  192 
scalenus  anticus,  123,  153 
niedius,  124 
posticus,  124 
semi  spinalis  colli,  160 
serratus  magnus,  3,  17,  124 
splenius  capitis,  122 
sterno-c  1  e  i  d  o  -  mastoideus, 
133,  137 
hyoideus,  144 
thyroideus,  144 
stylo-glossus,  173 
hyoideus,  144 
pharyngeus,  191 
subclavius,  17,  154 
subscapularis,  3,  17 
supinator  radii  brevis,  98 

longus,     59, 
65,  93 
supra-spinatus,  50 
temporalis,  163 
tensor  palati,  198 
teres  major,  3,  18.  49 
minor,  50 


INDEX. 


229 


Musculus  thyro-arytaenoideus,  210 
hyoideus,  144 
trapezius,  123 

triceps  extensor  Iiumeri,  39, 
51,  54,  59 
■Mylo-hyoid  artery,  16G 
muscle,  145 
nerve,  152 

Nares,  posterior,  195 
Nasal  artery,  113 

cartilages,  216 
duct,  219 
fossae,  216 
nerve,  115,  221 
Neck,  anterior  triangle,  141 
posterior  triangle,  124 
dissection  of,  121 
Nerve  of  latissinius,  25 

levator  anguli  scapulae,  189 
pterygoid  muscles,  170 
I'homboid  muscles,  134 
serratus  magnus,  25,  134 
subclavius,  134,  158 
teres  major,  25 
minor,  53 
Nervus  abducens  oculi,  108,  120 

accessorius  spinalis,  108, 134, 187 

auditorius,  108 

auricularis  magnus,  133,  152 

posterior,  134,  152 
auriculo-temporalis,  152,  170 
buccalis,  169 
buccinatorius,  169 
cardiaci,  186 
cardiacus  infer.,  188 
medius,  188 
super.,  188 
cervicales,  162,  189 
cervicalis  superficialis,  133, 141 
ciiiares,  115,  119 
circumfiexus,  11,  53 
cutaneous  externus  brachii,  25, 
36 
internus   major,    25, 
36 
minoi*,   25, 
36 
palmaris,  77 
dentalis  anterior,  179 
inferior,  170 
posterior,  179 
decendens  noni,  152,  158 


Nervus  diaphragmaticus,  158 
digastricus,  153 
digitalis,  median,  84 

radial,  70 

ulnar,  85 
dorsales  ulnaris,  85 
facialis,  108,  151,  180 
frontalis,  115 

glosso-pharyngeus,  108,  175, 185 
gustatorius,  170,  176 
hyoglossus,  109,  152,  175,  187 
infra-orbitalis,  180 
maxillaris,  140 
trochlearis,  115 
intercosto-cutanei,  11 
interosseus  anticus,  77 

posticus,  103 
lachiymalis,  114 
laryngeus  externus,  186,  193 
inferior,  186,  313 
superior,  186,  211 
massetericus,  183 
maxillaris  inferior,  168 
superior,  179 
medianus,  47,  70,  77,  84 
meningealis,  106 
motor  oculi,  107,  114,  120 
musculocutaneous  brachii,  25, 
36 

spiralis,  46,  61,  103 
mylo-hyoideus,  153 
nasalis,  115,  221 
occipitalis  major,  163 

minor,  133,  182 
olfactorius,  107,  221 
ophthalmicus,  114 
opticus,  107,  119 
orbitalis,  179 
palmaris  cutaneus  med.,  70 

ulnar,  77 
perforans  Casserii,  25,  36 
petrosis  magnus,  109 
pharyngeus,  186 
phrenicus,  158,  189 
pneumo-gastricus,  108,  158,  185 
radialis,  70 

recurrens  vagi,  186,  212 
spheno-palatinus,  179,  22i 
stylo-hyoideus,  152 
suboc.cipitalis  ram.  ant.,  189 
post.,  162 
subscapularis,  25 
supra-orbitalis,  114 


230 


INDEX. 


Nervus  supra-scapularis,  134,  158 
trochlearis,  115 
sympatheticus  cervicis,  187 
temporalis  profundus,  169 
temporo-facialis,  151 
thoracic!  anteriores,  25 
thoracicus  posterior,  25,  134 
thyro-hyoideus,  152 
trigeminus,  107 
trochlearis,  107,  114 
tympanicus,  185 
ulnaris,  47,  77,  85,  90 
Ninth  cranial  nerve,  108,  185 
Nose  cartilages,  216 
cavity,  216 
meatuses,  218 
mucous  membrane,  219 
nerves,  220 
vessels,  220 
Nostril,  216 
Nutritious  artery,  humeral,  45 

Obliquus  capitis,  inferior,  160 
superior,  160 
oculi,  inferior,  118 
superior,  111 
Occipital  artery,  150,  161 
sinus,  117 
nerv^e,  large,  162 

small,  133,  162 
CEsophagus,  aperture  of,  196 
Olecranon,  fracture  of,  55,  65 
Olfactory  nerve,  107,  220 

region,  220 
Oino-hyoid  muscle,  123,  144,  154 
Ophthalmic  artery,  113 

ganglion,  119 
nei^ve,  114 
vein,  113 
Opponens  pollicis  muscle,  86 
Optic  commissure,  106 

nei-ve,  107,  119 
Orbicularis  palpebrarum,  177 
Orbit,  dissection  of,  110,  117 
muscles,  111,  117 
nerves,  114 
vessels,  112 
Orbital  branch  of  nerve,  120,  179 
Os  hyoides,  201 

Palate,  soft,  197 

use  of,  200 
Palatine  arteries,  183 


Palato-glossus,  199 

pharyngeus,  199 
Palm  of  the  hand,  78 

dissection,  78 
cutaneous  nei'ves,  73 
Palmar  arch,  deep,  89 

sujaerficial,  81 
Palmaris  brevis,  79 
longus,  64 
Parotid  gland,  138 
Pectoralis  major,  2,  16 
minor,  2,  16 
Peculiarities  in  arteries 
axillary,  0 
brachial,  35,  44 
radial  in  forearm,  32,  68,  96 
subclavian,  129 
ulnar  in  forearm,  32 
in  palm,  83 
Perforating  arteries,  interosseous,  100 

palmar,  89 
Perforans  Casserli  nerve,  25,  36 
Petrosal  nei-ve,  large,  109 

sinuses,  116 

Pharynx,  dissection,  190 

interior,  193 

muscles,  190 

openings,  194 

Pharyngeal  ascending  artery,  183 

nerve,  186 
Phrenic  nerve,  158,  189 
Pillars  of  soft  palate,  197 
Pituitary  membrane,  219 
Plate 

1.  The  axilla 

2.  The  axillary  vessels 

3.  The  cutaneous  vessels  of  forearm 

4.  The  braclrial  vessels 

5.  The  shoulder  and  scapula 

6.  The  ann,  back 

7.  The  spiral  nerve  and  vessels 

8.  The  forearm,  front 

9.  The  foreami,  deep  view 

10.  The  palm  of  hand,  superficial  and 

deep  vie^vs 

11.  The  forearm,  back 

12.  The  forearm,  deep  view 

13.  The  base  of  skull  and  orbit,  super- 

ficial view 

14.  The  base  of  skull  and  orbit,  deep 

view 

15.  The  neck,  posterior  triangle 

16.  The  neck,  surface  view 


;  DEX. 


231 


Plate 

17.  The  neck,  anterior  triangle 

18   The  subclavian  vessels 

19.  The  neck,  view  behind 

20.  The  pterygoid  region 

21.  The  pterygoid,  deep  view 
23.  The  submaxillary  region 

23.  The  upper  maxillary  nerve 

24.  The  internal  carotid  artery 

25.  The  pharynx,  surface  view 

26.  The  pharynx,  interior 

27.  The  larj'nx  and  vocal  appai'atus 

28.  The  nose  cavity 
Platysma  myoides,  121 
Plexus  brachial,  25,  158,  189 

cervical,  133,  189 
pharyngeal,  186 
Plugging  the  nares,  217 
Pneumo-gaotric  nerve,  108,  158,  185 
Pomum  Adcmi,  203 
Portio  dura,  108 

mollis,  1C3 
Posterior  triangle  ci  i.  ick,  <  ^4 
Pouch  laryngeal,  207 
Profunda  artery,  arm,  45 

neck,  161 
Pronator  quadratus,  72 
radii  teres,  63 
Pterygoid  arteries,  166 

nei-ves,  170,  171 
Pteiygoideus  externus,  164 
internus,  164 
Pterygo-maxillary  region,  163 

Radial  artery,  68,  88,  96 
nerve,  70 
veins,  68 
Radius,  fracture,  73 

movement,  73 
Ranine  artery,  175 
Rectus  capitis  anticus  major,  181 
minor,  183 
posticus  major,  160 
minor,  160 
lateralis,  181 
oculi  externus,  112,  118 
inferior,  118 
internus,  118 
superior,  112 
Recurrent  interosseous  artery.  101 
radial,  69,  101 
ulnar  anterior,  76 


Recux-rent  ulnar  posterior,  76 

nerve, 186,  213 
Rhomboideus  major,  49 
minor,  50 
Rima  glottidis,  307 

Sacculus  laryngis,  2^7 
Salpingo-pharyngeus,  i93 
Scaleni  muscles,  123,  153 
Scapxilar  artery,  posterior,  i8> 

muscles,  17,  48 
Schneiderian  membrane,  319 
Second  ci'anial  nerve,  107,  119 
Semi-spinalis  colli,  160 
Septum  nasi,  216 

Serratus  magnus  muscle,  3,  17,  135 
Seventh  cranial  nerve,  108 
Sheath,  axillary,  19 

digital  of  fingers,  80 
Sinuses  of  the  skull,  116 
Sixth  cranial  nerve,  1 08 
Soft  palate,  197 

use  of,  200 
Spheno-palatine  nerves,  179,  331 
Spinal  accessory  nerve,  108,  134,  187 
Splenius  capitis,  133 
Spongy  bones,  218 
Stenon's  duct,  138 
Sterno-cleido-mastoideus,  123,  137 
hj'oideus,  144 
thyroideus,  144 
Straight  sinus,  117 
Stylo- hyoid  ligament,  173 
hyoideus,  144 
glossus,  173 

maxillary  ligament,  171 
pharyngeus,  191 
Subanconeous  muscle,  59 
Subclavian  arterj^,  137,  154 

vein,  157 
Subclavius  muscle,  17,  154 
Sublingual  artery,  175 

gland,  139,  174 
Submaxillary  ganglion,  176 
gland,  139,  174 
region,  173 
Submental  vessels,  150 
Suboccipital  nerve,  ant.  branch,  189 
post,  branch,  163 
Subscapular  nerve,  35 
vessels,  8 
Subscapularis  muscle,  3,  17 


232 


INDEX. 


Superficial  cervical  artery,  131 

nerve,  133,  141 
volar  ai'tery,  69 
Supinator  radii  brevis,  98 

longus,  59,  65,  92 
Supra-orbital  artery,  113 
nerve,  114 
scapular  artery,  130,  156 
nerve,  134,  158 
vein,  157 
spinatus  muscle,  50 
trochlear  nerve,  115 
Spermatic  cord,  cervical,  187 

Temporal  arteries,  150,  166 
muscle,  163 
nerve,  169 
Temporo-facial  nerve,  152 
Tensor  palati,  198 
Tenth  cranial  nerve,  108,  185 
Tentorium  cerebelli,  105 
Teres  major  muscle,  2,  49 

minor  muscle,  50 
Third  cranial  nerve,  107,  114,  119 
Thoracic  nerve,  posterior,  134 
acromial  artery,  23 
alar,  8,  23 
humeral,  23 
long,  8,  23 
superior,  23 
Thyro-arytsenoid  articulations,  206 
muscle,  210 
epiglottid  ligament,  205 
hyoid  membrane,  205 
muscle,  144 
nerve,  152 
Thyroid  artery,  inferior,  156,  182,  214 
superior,  150,  183,  214 
axis,  156 
body, 214 
cartilage,  202 
veins,  214 
Tonsil,  197 

ai-tery  of,  188 
Torcular  Herophili,  117 
Trachea,  connections,  215 

structure,  215 
Tracheal  glands,  215 
Transverse  cervical  artery,  131,  156 
vein,  157 
sinus,  116 
l!rapezius  muscle,  122 


Triangle  of  neck,  anterior,  141 
posterior,  124 
Triangular  cartilage,  nasal,  217 
Triceps  extensor  cubiti,  51,  54,  59 
Trigeminal  cranial  nerve,  107 
Trochlea,  111 

Trochlear  nerve,  infra,  115 
supra,  115 
Turbinate  bones,  218 
Twelfth  cranial  nerve,  109,  175,  1S7 
Tympanic  artery,  183 

Ulnar  artery,  69,  74 

nerve,  47,  77,  85,  90 
veins,  deep,  75 

superficial,  28 

Vagus  cranial  nerve,  108,  185 
Vein,  alveolar,  167 

auricular  posterior,  151 
axillary,  9 
basilic,  29 
brachial,  40 
cephalic,  24,  30 
deep  cervical,  161 
facial,  166 

deep,  167 
innominate,  157 
jugular  anterior,  149,  157 

external,  131,  149,  151 
internal,  151,  157 
laryngeal,  213 
lingual,  175 
median  of  forearm,  28 
basilic,  29 
cephalic,  29 
maxillary  internal,  151,  167 
nasal,  220 
ophthalmic,  113 
pterygoid,  167 
radial  cutaneous,  29 

deep,  68 
subclavian,  156 
temporal,  151 
thyroid,  214 
ulnar  cutaneous,  28 

deep,  75 

vertebral,  155,  161 

Vena  cava  superior,  157 

Ventricle  of  larynx,  207 

Vertebral  artery,  109,  156,  ISl 

vein,  155,  161 


INDEX. 


233 


Vessels  of  dura  mater,  105 
Vocal  cords,  206 

use  of,  207 

Wounds  of  arteries, 

brachial,  32,  34 

palmar  arch,  supei'licial,  82 


Wounds  of  arteries, 

j)almar  arch,  deep.  90 

radial,  68 

ulnar  in  forearm,  76 
Wharton's  duct,  j;74 
Wrisberg's  nerve,  864  1-6 
cartilages.  204 


INDEX    TO    VOLUME    II. 


INDEX. 


Abdomen,  55 
Abdominal  aorta,  61 

hernia,  38,  43 
ring,  external,  30 

internal,  36,  49 
wall,  27,  48 
Abductor  minimi  digiti  pedis,  186 

pollicis  pedis,  186 
Accelerator  urinse  muscle,  19 
Accessorius  muscle,  193 
Accessory  nerve  of  obturator,  134 

pudic  artery,  87 
Adductor  brevis,  129 
hallucis,  196 
longus,  128 
magnus,  129,  158 
Anastomosis  of  arteries 
in  the  foot,  188,  201 
at  the  knee,  163,  174 
in  the  thigh,  126,  160 
Anastomotic  artery  of  femoral,  120 

branches  of  profunda,  160 
Annular  ligament  of  ankle,  anterior,  210 
external,  212 
internal,  177 
Aorta  abdominal,  61 
Aortic  opening,  58 
Aperture  of  diaphragm,  58 
for  vena  cava,  58 
Aponeurosis  of  external  oblique,  29 
fascia  lata,  28 
femoral  artery,  117 
internal  oblique,  33 
transversalis,  36 
Appendages  of  uterus,  94 
Arch  crural  or  femoral,  48 
diaphragmatic,  57 
plantar, 
of  urethra,  86 
Artery,  anastomotic  femoral,  120 
aorta,  abdominal,  61 
articular  azygos,  154,  163 


Artery  articular  inferior,  174 

superior,  154,  163 
bulbous,  25 
capsular,  middle,  61 
circumflex,  external,  126 

iliac  internal,  38,  54 
iliac  superficial,  28, 

98 
internal,  132,  149 
coccygeal,  142 

companion  of  sciatic  nerve,  142 
cremasteric,  38 
diaphragmatic,  61 
digital  of  foot,  188,  201 
dorsal  of  foot,  203,  213 

penis,  76 
epigastric  internal,  38,  54 

superficial,  28,  93 
femoral,  115 
gluteal,  68,  141,  148 
hsemorrhoidal  inferior,  14 
middle,  68 
superior,  88 
hypogastric,  76 
ilio-luinbar,  67 
iliac  common,  62 

external,  53,  62 
internal,  63,  67 
intercostal  lowest,  67 
interosseus  of  foot,  214 
ischiatic,  14,  68,  142 
large  of  great  toe,  203 
lumbar,  61,  66 
malleolar  inner,  213 
outer,  213 
metatarsal,  214 
nutritious  of  femur,  131 
fibula,  183 
tibia,  182 
obturator,  54,  68 
ovarian,  96 
perforating,  femoral,  132.  160 


220 


INDEX. 


Artery,  perforating,  of  foot,  202 
perinseal  superficial,  20 
peroneal,  182 

anterior,  183,  214 
phrenic  inferior,  61 
plantar,  external,  188,  198 

internal,  187 
popliteal,  160,  173 
profunda  femoral,  125,  131 
pudic  external,  28,  98,  119 

internal,  14,  25,  76 
recurrent  tibial,  213 
renal,  61 

sacral,  lateral,  68 
middle,  61 
sciatic,  14,  68,  143 
spermatic,  61 
supra-renal,  61 
tarsal,  214 
tibial  anterior,  179,  203,  212 

posterior,  179 
transverse  perinasal,  20,  25 
uterine,  96 
vaginal,  96 
vesical  inferior,  88 
superior,  88 
Articular  popliteal  arteries,  163, 174,  175 

nerves,  165 
Azygos  artery,  163 

vein,  large,  68 

Biceps  femoris,  157 
Bladder  connections,  male,  82 
female,  91 
ligaments,  false,  79,  83 
true,  83 
Broad  uterine  ligament,  93 
Bulb  of  the  urethra,  23 
artery  of,  25 
nerve  of,  26 

Capsular  artery,  middle,  61 

Cava  inferior,  63 

Central  point  of  perineeum,  18 

tendon  of  diaphragm,  57 
Circumflex  artery,  external,  126 
internal,  132 
iliac  artery,  deep,  38,  54 

superficial,  28, 
98 
Coccygeal  artery,  142 
Coccygeus  muscle,  74 


Comes  nervi  ischiadici,  143 
Communicating  peroneal  nerve,  167" 
Compression  of  arteries 

popliteal,  162 
Congenital  hernia,  42 
Conjoined  tendon,  36 
Constrictor,  ui'ethrai,  24 
vaginal,  93 
Cordiform  tendon,  57 
Corrugator  cutis  ani,  11 
Cowper's  glands,  23 
Cremaster  muscle,  34 
Cremasteric  artery,  38 
Cribriform  fascia,  101 
Crura  of  the  diaphragm,  57 
Crureus  muscle,  124 
Crural  arch,  48,  102 

deep,  103 
canal,  104 
hernia,  105 
nerve,  70 
ring,  50 
sheath,  49,  103 
Curve  of  the  urethra,  86 
Cutaneous  nerves  of  abdomen,  32 
buttock,  135 
foot,  back,  205 
sole,  189 
leg,  back,  166 
front,  205 
perinaeum,  14,  20 
thigh,  front,  109 

Deep  crural  arch,  103 

transverse  perinseal  muscle,  18, 
24 
Diaphragm,  56 

vessels  of,  61 
Digital  arteries,  plantar,  188 
tibial,  214 
nerves  of  plantar,  189 
Dissection  of  abdominal  cavity,  55 
wall,  27,  47 
buttock,  134 
femoral  hernia,  103 
foot,  back,  204 
sole,  184 
groin,  27 
ham,  151 

inguinal  hernia,  27 
leg,  back,  166 
front,  204 


INDKX. 


221 


Dissection  of  lower  limb,  97 

lumbar  ple^ius,  65 
pelvis,  female,  90 

male,  73 
perinaeum,  back,  9 

front,  16,  21 
popliteal  space,  151 
sacral  plexus,  65 
saphenovis  opening,  97 
Scarpa's  space,  111 
thigh,  back,  156 
front,  108 
vena  cava  inferior,  55 
Dorsal  artery  of  foot,  203,  213 

nerve  of  penis,  77 
Ductus  thoracicus,  68 

Ejaculatoe  uringe,  19 
Epigastric  artery,  deep,  38,  54 

superficial,  28,  98 
Erector  penis,  19 
Extensor  digitorum  brevis,  209 

longus  pedis,  208 
proprius  poUicis,  209 
External  cutaneous  nerve  of  thigh.  70, 
109 
oblique  muscle,  29 
saphenous  nerve,  167,  206 
Extravasation  of  urine,  17,  87 

Falciform  edge  of  saphenous  opening, 

100 
Fallopian  tube,  94 
Fascia,  cremasteric,  39 
cribriform,  101 
iliac,  49 
lata,  100 
perinseal,  deep,  23 

suiierficial,  17 
propria,  105 
recto- vesical,  78 
spermatic,  39 
transversalis,  36,  48 
Fat  in  ischio-rectal  fossa,  13 

popliteal  space,  156 
Femoral  artery,  116 
hernia,  102 
ligament,  101 
vein,  120 
Fimbriae  of  Fallopian  tube,  94 
Fissure  for  splanchnic  nerves,  58 
Flexor  minimi  digiti  pedis,  196 


Flexor  digitorum  pedis  brevis,  185 
longus,  177 
pollicis  longus  pedis,  177 
brevis  pedis,  195 
Foot,  dorsum,  204 

sole,  184 
Fossa  ischio-rectal,  12 
Fossae  of  abdominal  vrall,  48 

Ganglia  lumbar,  71 

sacral,  72 
Gastrocnemius  muscle,  170 
Gemellus  inferior,  140 
superior,  140 
Genito-crural  nerve,  55,  70,  109 
Gimbernat's  ligament,  48 
Gland,  prostatic,  85 
Glands,  Cowper's,  23 

inguinal,  28,  99 

lumbar,  60 

popliteal,  155 
Gluteal  artery,  68,  141 

nerve,  superior,  70,  126,  150 

nerves,  inferior,  143 
Gluteus  maximus,  136,  157 

medius,  138 

nainimus,  145 
Gracilis  muscle,  128 

Ham,  151,  169 

Haemorrhoidal  arteries,  14,  68,  88 
nerve  inferior,  15 
plexus  of  veins,  89 
Haemorrhoids,  10 
Hernia,  femoral,  103 

its  course,  51,  105 

coverings,  51,  105 

diagnosis,  106 

stricture,  52,  107 

femoral,  operation,  52,  106 

the  taxis,  51,  106 

truss,  application,  106 

inguinal  external,  38 

its  course,  38 

coverings,  39 

diagnosis,  39 

stricture,  41 

operation,  41 

the  taxis,  40 

truss,  application,  40 

varieties,  42 


99,9, 


INDEX. 


Hernia,  inguinal  internal,  43 

its  course,  43,  47 

coverings,  44,  46 

diagnosis,  44,  46 

stricture,  45,  47 

operation,  45,  47 

taxis,  45,  46 

truss,  application,  45,  46 

varieties,  46 

obturator,  50 
Hesselbach's  space,  43 
Hollow  behind  knee,  151,  169 
Hypogastric  artery,  76 
plexus,  89 

Iliac  artery,  common,  62 

external,  52,  62 
internal,  62 
fascia,  49 
veins,  63 
Iliacus  muscle,  60,  130 
Ilio-hypogastric  nerve,  32,  34,  70 
inguinal  nerve,  82,  35,  70 
lumbar  artery,  67 
vertebral  ligament,  69 
Infantile  hernia,  42 
Inguinal  canal,  88 

glands,  28,  99 
hernia,  external,  38 
internal,  43 
Intercolumnar  fibres,  29 
Internal  cutaneous  of  thigh,  110,  121 
oblique  muscle,  33 
saphenous  nerve,  110,  121 
vein,  99,  111 
Interosseous  arteries  of  foot,  214 
muscles  of  foot,  199 
Ischio-rectal  fossa,  12 

Kidney,  56 

Laege  artery  of  great  toe,  208 
Last  dorsal  nerve,  34,  65,  71 
Leg,  dissection  of  back,  166 
front,  204 
Levator  ani,  12,  74 
Ligaments  of  the  bladder,  79,  83 
ovary,  95 
uterus,  94 
Ligamentum  arcuatum  inter. ,  57 
exter.,  58 
longum  plantse,  193 


Ligature  of  arteries 

dorsal  artery  of  foot,  215 
femoral,  118 
iliac,  common,  62 
external,  53 
internal,  67 
popliteal,  162 
tibial  posterior,  180 
Limb,  lower,  dissection  of,  97 
Linea  alba,  30 

semilunaris,  80 
Lithotomy,  parts  cut,  15,  26,  86 
Lumbar  arteries,  61 
ganglia,  71 
glands,  60 
plexus,  69 
veins,  67 
Lumbo-sacral  nerve,  70 
Lumbricales  of  foot,  194 
Lymphatics  of  groin,  99 
ham,  155 
leg,  216 
loins,  60 

Malleolar  arteries,  218 
Membranous  part  of  urethra,  22 
Mesenteric  artery,  inferior,  61 
superior,  61 
vein,  inferior,  64 
superior,  64 
Meso-rectum,  81 
Metatarsal  artery,  214 
Musculo-cutaneous  nerve  of  leg,  206, 217 
Musculus  abductor  minimi  digiti  pedis, 
186 
pollicis  pedis,  186 
accessorius  pedis,  198 
adductor  brevis,  129 
haliucis,  196 
longus,  128 
magnus,  129,  158 
biceps  femoralis,  157 
coccygeus,  74 
constrictor  urethrse,  24 
vaginee,  93 
corrugator  cutis  ani,  11 
cremastericus,  34 
diaphragmatis,  56 
ejaculator  urinse,  19 
erector  penis,  19 
extensor    brevis     digitorum 
pedis,  209 


INDEX. 


223 


Musculus  extensor  longus    digitorum 
pedis,  209 
ossis  hallucis,  209 
flexor  accessorius,  193 

brevis    minimi    digiti 

pedis,  196 
digitorum  brevis,  185 
digit,     longus    pedis, 

177,  193 
hallucis  brevis,  195 

longus,  177,  193 
gastrocnemius,  170 
gemellus  inferior,  140 

superior,  140 
gluteus  maximus,  136,  157 
medius,  138 
minimus,  145 
gracilis,  128 
iliacus,  60,  130 
interossei  pedis,  199 
levator  ani,  12,  74 
lumbricales  pedis,  194 
obturator  externus,  130,  140, 
146 
internus,  139,  146 
orbicularis  urethrse,  24 
pectineus,  127 
peroneus  brevis,  211 
longus,  211 
tertius,  208 
plantaris,  171 
popliteus,  176 
psoas  magnus,  58,  130 

parvus,  59 
pyriformis,  74,  139 
quadratus  femoris,  140 

lumborum,  59 
rectus  femoris,  123 
sartorius,  113 
senii-membranosus,  158 

tendinosus,  157 
soleus,  173 

sphincter  ani  externus,  11 
internus,  11 
subcrureus,  185 
tensor  vaginse  femoris,  123 
tibialis  anticus,  209 

posticus,  178,  200 
transversalis  pedis,  196      [18 
perinaei  supei'f . , 
pro  fund., 
24 


Musculus  triceps  extensor  femoris,  123 
vastus  externus,  123 
internus,  124 

Nerve  of  coccygeus,  89 

external  sphincter,  89 
gemellus  and  quadratus,  144, 
151 
superior,  144 
levator  ani,  89 
obturator  internus,  144 
pectineus,  127 
tensor  vagina  femoris,  150 
vasti  muscles,  121,  137 
Nervus  accessorius  obtui-ator,  134 
communicans  peronei,  165 
cruralis,  70,  120 
cutaneus  externus  femoris,  70, 
109 
internus  femoris,  110, 

131 
medius  femoris,  109 
plantaris,  183,  189 
digitales,  plantar.,  189,  190 
dorsales,  33 
dorsalis  penis,  77 
genito-cruralis,  55,  70,  109 
gluteus  inferior,  143 

superior,  70,  136,  150 
hsemorrhoidalis  inferior,  15 
ilio-hypogastricus,  38,  34,  70 

inguinalis,  33,  35,  70 
ischiadicus  major,  144,  164 

minor,  15,  135,  143 
lumbales,  69,  135 
lumbo-sacralis,  70 
musculo-cutaneus  cruris,  806 
obturatorius,  70,  110,  133,  165 
patellaris,  110,  181 
perineealis  superficialis,  15,  30 
peronealis  communis,  167 
phrenicus,  65 
plantaris  externus,  190, 197,  204 

internus,  189 
popliteus    externus,    155,   165, 
175 
internus,    155,    164, 
175 
pudendus  inferior,  20,  143 
pudicus  internus,  14,  86,  76 
recurrens  articularis,  217 
sacrales,  71 


224 


INDEX. 


NervTis  sacrales  posteriores,  150 
saphenus  externus,  206 

internus,  110,  121 
sciaticus  magnus,  144,  163,  166 
parvus,  15,  135,  143, 167 
splanchnicus  major,  72 
minor,  72 
sympatheticus  abdominis,  71 
pelvis,  71,  90 
tibialis  anticus,  206,  317 

posticus,  183 
uterini,  97 
vaginales,  97 
Nutritious  artery  femoral,  131 
fibular,  183 
tibial,  182 

Obliquus  abdominis  externus,  29 
internus,  33 
Obturator  artery,  68 

muscle,  external,  130, 140, 146 

internal,  139,  146 
nerve.  70,  110,  133,  165 
(Esophageal  opening  of  diaphragm,  58 
Orbicularis  iirethr^,  24 
Os  tincse,  92 
Ovaries,  95 

arteries,  97 
nerves,  97 

Patella  branch,  110 
plexus,  110 
Pectineus  muscle,  128 
Peculiarities  in  arteries 

dorsal  artery  of  foot,  215 
femoral,  117 
iliac,  common,  62 
external,  54 
internal,  67 
profunda  femoral,  117 
popliteal,  162 
tibial  anter.,  213 
poster.,  183 
Pelvis,  female,  90 

dissection,  90 
male,  73 
Pelvic  fascia,  77 
plexus,  90 
Perforating  arteries,  femoral,  132,  160 

plantar,  202 
Perinseum,  male,  9 
Perinseal  fascia,  deep,  22 


Perinaeal  fascia,  superficial,  17 

nerves,  14,  20 
Peritoneal  process,  with  cord,  37 
Peritoneum  of  hernia,  37 

pelvis,  male,  83 

female,  93 
Peroneal  artery,  182 

anterior,  183,  214 
communicating  nerve,  167 
Peroneus  brevis,  211 

longus,  200,  211 
tertius,  208 
Phrenic  nerve,  65 
Piles,  10 
Pillars  of  abdominal  ring,  30 

diaphragm,  57 
Plantar  arteries,  187,  198,  201 
ligament,  long,  195 
nerves,  189,  197,  204 
vessels,  187,  198,  201 
Plantaris  muscle,  171 
Plate 

29.  The  perinasum,  anal  half 

30.  The  perinaeum,  anterior  half 

31.  The  perinseum,  triangular  ligament 

32.  The  groin,  surface  view 

33.  The  groin,  deep  view 

34.  The  gi-oin,  deep  part 

35.  The  groin,  inner  view 

36.  The  abdomen,  deep  vessels 

37.  The  lumbar  and  sacral  plexuses 

38.  The  pelvis,  side  muscles 

39.  The  pelvis,  recto-vesical  fascia 

40.  The  pelvis,  the  viscera 

41.  The  pelvis,  female,  side  view,  viscera 

42.  The  gi'oin,  vessels  of 

43.  The  groin,  crural  sheath 

44.  The  thigh,  surface  view 

45.  The  tliigh,  femoral  vessels 

46.  The  thigh,  extensor  muscles 

47.  The  thigh,  adductor  muscles 

48.  The  buttock,  surface  view 

49.  The  buttock,  second  stage 

50.  The  buttock,  third  stage 

51.  The  popliteal  space 

52.  The  thigh,  back,  deep  view 

53.  The  leg,  back,  surface  view 

54.  The  leg,  back,  soleus  and  plantaris 

55.  The  leg,  back,  deep  view 

56.  The  sole  of  foot,  two  superf .  views 

57.  The  sole  of  foot,  two  deep  views 

58.  The  leg,  fore  part 


INDEX. 


225 


Plexus  lumbar,  69 
pelvic,  90,  97 
sacral,  71 
Popliteal  artery,  160,  173 
glands,  155 
nerves,  155,  1G4,  175 
space,  151,  1G9 
vein,  154 
Popliteus  muscle,  176 
Poupart's  ligament.  30 
Profunda  artery,  thigh,  120,  125,  131 
branches,  159 
Prostate  gland,  85 

connections,  85 
sheath,  78 
structure,  86 
Prostatic  part  of  urethra,  92 
Psoas  magnus,  58,  130 

parvus,  59 
Pudendal  nerve,  inferior,  20,  143 
Pudic  artery  superficial,  28,  98,  119 
deep,  14,  25,  76 
nerve,  14,  26 
Puncturing  bladder,  82 
Pyriformis  muscle,  74,  139 

QuADRATUS  femoris,  140 

lumborum,  59 

Receptaculum  chyli,  68 
Recto-uterine  pouch,  94 
Recto-vesical  fascia,  78 
pouch,  84 
Rectus  femoris,  123 
Rectum  connections,  male,  10,  81 
female,  91 
sheath,  79 
Recurrent  tibial,  213 

branch,  217 
Renal  artery,  61 

vein,  64 
Ring,  abdominal  external,  80 

internal,  36,  49 
crural,  50 
Round  ligament  of  uterus,  94 

Sacral  artery  lateral,  68 
middle,  61 
ganglia,  72 
nerves,  71 

posterior,  150 
plexus,  71 


Saci-o-sciatic  ligaments,  147 

notches,  147 
Saplienous  nerve  external,  167,  206 

internal,  110,  166,  20'? 
opening,  100 
vein  external,  168,  205 

internal,  99,  111,  205 
Sartor ius  muscle,  113 
Scarpa's  triangular  space.  111 
Sciatic  artery,  14,  68 

nerve  large,  144,  164,  167 
small,  15,  135,  143 
Semi-membraiiosus  muscle,  158 

tendinosus  muscle,  157 
Septum  crurale,  50,  104 
Sheath,  crural,  49,  103 

digital  of  toes,  193 
Sole  of  foot,  dissection  of,  184 
Soleus  muscle,  172 
Spermatic  artery,  61 
cord,  31,  37 
fascia,  39 
vein,  54 
Sphincter  anl  externus,  11 
internus,  11 
vaginae,  93 
Splanchnic  nerves,  72 
Spongy  part  of  urethra,  23 
Subcrureus  muscle,  135 
Subperitoneal  fat,  37 
Subpubic  aperture,  50 
Superficial  fascia,  abdominal,  27 
perinaeal,  17 
femoral,  27,  100 
peringeal  fascia,  17 
Supra-renal  capsule,  56 

vessels,  61,  64 
Sympathetic  cord,  abdominal,  71 
pelvic,  73,  90 

Tarsal  artery,  314 
Tendo  Achillis,  173 

rupture,  173 
Tendon  of  extensor  cruris,  124 
Tensor  vaginae  femoris,  123 
Thigh,  dissection  of,  108 
Thoracic  duct,  68 

Tibial  artery,  anterior,  179,  203,  213 
posterior,  179 
nerve  anterior,  180,  317 
posterior,  180,  183 
veins,  anterior,  215 


226 


INDEX. 


Tibial  veins,  posterior,  180 
Tibialis  anticus  muscle,  207 

posticus,  178,  200 
Transverse  ligament  pedal,  186 

perineal  artery,  20 
Transversalis  abdominis,  36 

fascia,  36 
Transversus  pedis  muscle,  196 
perinaei  superf.,  18 
deep,  24 
Triangular  ligament  of  urethra,  22,  7 
space  of  gi'oin,  43 
thigli.  111 
perineeum,  19 
Triceps  extensor  cruris,  123 

Uketer,  83,  92 
Urethra,  female,  91 

connections,  91 
male,  22 
curve  of,  86 
incision  into,  21,  26 
rupture,  21 
Uterine  appendages,  94 
arteiy,  96 

plexus  of  nerves,  97 
Uterus,  92 

connections,  92 
ligaments,  93 

Vagina,  connections,  93 

Vaginal  vessels,  96 

Vas  deferens,  84 

Vastus  extemus,  123 

internus  muscle,  124 

Vein,  azygos  large,  68 
cava  inferior,  63 
circumflex  iliac  deep,  38 

superf.,  28,  98 
diaphragmatic  inferior,  64 


Vein,  dorsal  arch  of  foot,  204 
epigastric  deep,  38 

superficial,  28,  98 
femoral,  120 
gluteal,  149 

hemorrhoidal,  upper,  88 
iliac,  common,  63 
external,  63 
internal,  63 
lumbar,  67 

mesenteric  inferior,  64 
superior,  64 
perinseal  superficial,  20 
peroneal,  183 
popliteal,  154,  163 
portal,  64 

profunda,  femoral,  132 
pudic  external,  28,  99 
internal,  14,  25 
renal,  64 
saphenous  external,  168,  205 

internal,  99,  111,  108, 
•  205 
spermatic,  64 
supra-renal,  64 
tibial  anterior,  215 
posterior,  103 
Vena  cava  inferior,  63 

portaB,  64 
Venae  cavse  hepaticee,  64 
Venous  arch  of  foot,  204 
Vesica  urinaria,  82,  91 
Vesical  arteries,  68,  88 
Vesico-uterine  pouch,  94 
Vesiculse  seminales,  85 

Wounds  of  arteries 

dorsdl  of  foot,  216 
plantar  arch,  203 
tibial  post,  181 


llluslialiods  of  dissections  in  a  series 


Qn^^ 


\\>^ 


\A'V.c.xvY-°*^^    ^ic  "V^v'^'^^.oWon^ 


